351c Build Ideas And Advice

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Zach

Well-known member
Joined
Jul 7, 2023
Messages
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Location
Minnesota
My Car
1971 Mustang Mach 1 351c 4 speed
Howdy yall,

Getting close to being able to throw an engine in the mustang so I want to at least get a plan going.

It will be a street car and driven quite a bit but at the end of the day its a hot rod, it will be spinning tires, chugging gas, and hitting WOT for some smiles, not to mention my mom wants to show off to her hot rod friends. It is my mom's car (her credit card) so I am open to pretty much anything and want to go the power route, she is OK with dumping money into it just within reason obviously. Ideally I want to build a 408 stroker with a hyd roller cam, just for coolness factor and being slightly unique, I'm sure a hopped up 351 runs great though. I have yet to get the block checked out, original M code blew up before I was born and it was replace with a 73 block, Ill post numbers and stuff below. Seems to be a solid block, not bored, cylinders still look great, I got the 2v heads disassembled, cleaned, and checked for cracks, just to see what I am working with, shop said they look great besides needing a valve job, shop said they had performance springs and valves already which is interesting but I am getting all new everything anyways so it doesn't matter. Curious if getting the 2v heads fit for a 408 is even worth it or if I should just go with aluminum heads or something else for the price, it won't live in the high rpms most the time so I am not to concerned about the upper power band. In terms of HP, I am fine with making the lower end of what 408s put out, I don't need to maximize outputs at all. I will be assembling most of it myself outside of sending it out for machine work and head work.

This is what I have currently.
351c stock block: d2ae-ca, 3a3
2v heads: d1ae 2j27, d1ae 3a4
Factory 4 speed top loader
3.25 t-lok diff, think it needs a rebuild though I haven't cracked it open yet
Hooker comp headers, I can return or sell if I need a head swap.
Holley Sniper 2 EFI, wanted to try something different, seems the 2 unit has significantly better reviews than 1 which is why I considered it
Holley Hyperspark 2 distributor + ignition box
In terms of clearance, naca hood, power steering+brake, headers

Planning on a 2.5 inch dual exhaust all the way back with dynomax super turbos. Intake depends on what you guys advise, I was planning on a rpm performer air gap but that also depends on the opinion on the heads.

Lemme know if you guys want any more info or anything. I tinker with Pontiacs for the most part so all the ford stuff is new to me. Just want to get some input on my current idea, nothing is set in stone. Original plan was to just throw the engine back together stockish which is why I have a lot of these parts already but its out so I might as well just go for it.
Thanks.

Heads/piston pics for curiosity,
image_6209779.JPGimage_123650291.JPG
 
We had a recent thread where somebody mentioned the holley sniper throttle body style EFI run better with a single plane intake.

I probably wouldn't worry about aftermarket heads. That was the cleveland's big claim to fame. The iron heads flow plenty good enough.
 
Mine is the original 351C-2V warmed up with CompCams and Edelbrock goodies. I wish the 'Garage' threads were still around, as the 'recipe' for my engine was outlined there. Suffice it to say:

  • Original 351 Cleveland
    - Machine work by Winger's Automotive
    - Balanced, Blueprinted, Magnafluxed
    - Bored .060"
    - 3-angle valve job, mild port & polish
  • Edelbrock 351C-2V Performer intake
  • Edelbrock 1406 Performer 600CFM carb
  • Holley electric fuel pump
  • CompCams High-Energy 270/270 @ .566" roller cam
  • CompCams High-Energy lifters & pushrods
  • CompCams High-Energy 1.73 roller rockers
  • Crane Cams 7/16" screw-in rocker studs
  • Keith Black 9.5:1 hypereutectic flat-top pistons
  • Duraspark II ignition and distributor
  • Accel Super-Coil & 8mm wires
  • Hooker Competition ceramic-coated headers
  • Pypes Street Pro mufflers
  • Pypes 2.5" stainless exhaust with 'X' pipe
  • Pypes 2.5" chrome 'slash' tips
This set-up is worth 406hp at the crank, according to CompCams CamQuest utility (which I used to spec out the cam based on the things I did to the engine). The standard-sized Duraspark distributor works with the factory-style Ram Air air cleaner without modification, the Performer intake is the same deck height as the factory 2V intake, and the 1406 carb is the same height as the factory carb, so no hood clearance issues there.

Here's a quick video my buddy took to share with is friend as we were getting ready to head out to a car show:
View attachment Frankenstang_20180928[1].mp4

Don't forget to make it pretty:
1715989318487.png

Hope this helps.
 
Mine is the original 351C-2V warmed up with CompCams and Edelbrock goodies. I wish the 'Garage' threads were still around, as the 'recipe' for my engine was outlined there. Suffice it to say:

  • Original 351 Cleveland
    - Machine work by Winger's Automotive
    - Balanced, Blueprinted, Magnafluxed
    - Bored .060"
    - 3-angle valve job, mild port & polish
  • Edelbrock 351C-2V Performer intake
  • Edelbrock 1406 Performer 600CFM carb
  • Holley electric fuel pump
  • CompCams High-Energy 270/270 @ .566" roller cam
  • CompCams High-Energy lifters & pushrods
  • CompCams High-Energy 1.73 roller rockers
  • Crane Cams 7/16" screw-in rocker studs
  • Keith Black 9.5:1 hypereutectic flat-top pistons
  • Duraspark II ignition and distributor
  • Accel Super-Coil & 8mm wires
  • Hooker Competition ceramic-coated headers
  • Pypes Street Pro mufflers
  • Pypes 2.5" stainless exhaust with 'X' pipe
  • Pypes 2.5" chrome 'slash' tips
This set-up is worth 406hp at the crank, according to CompCams CamQuest utility (which I used to spec out the cam based on the things I did to the engine). The standard-sized Duraspark distributor works with the factory-style Ram Air air cleaner without modification, the Performer intake is the same deck height as the factory 2V intake, and the 1406 carb is the same height as the factory carb, so no hood clearance issues there.

Here's a quick video my buddy took to share with is friend as we were getting ready to head out to a car show:
View attachment 88825

Don't forget to make it pretty:
View attachment 88826

Hope this helps.
Nice set up, how is the comp cams components working out for you? Was reading some forum posts saying they aren’t the best. I guess that is with everything though lol. Also any reason why you went over 60 and is it safe with a Cleveland?
 
Rom air gap has a notch milled into the plenum to add a little single plane signal.

I would recommend it for the EFI.

Dual pattern cams will also help.

Make sure you get rid of the stock valves and mill the rocker pedestals for adjustable rockers.

I do have a set of heads with all the work done. I went aftermarket
 
Howdy yall,

Getting close to being able to throw an engine in the mustang so I want to at least get a plan going.

It will be a street car and driven quite a bit but at the end of the day its a hot rod, it will be spinning tires, chugging gas, and hitting WOT for some smiles, not to mention my mom wants to show off to her hot rod friends. It is my mom's car (her credit card) so I am open to pretty much anything and want to go the power route, she is OK with dumping money into it just within reason obviously. Ideally I want to build a 408 stroker with a hyd roller cam, just for coolness factor and being slightly unique, I'm sure a hopped up 351 runs great though. I have yet to get the block checked out, original M code blew up before I was born and it was replace with a 73 block, Ill post numbers and stuff below. Seems to be a solid block, not bored, cylinders still look great, I got the 2v heads disassembled, cleaned, and checked for cracks, just to see what I am working with, shop said they look great besides needing a valve job, shop said they had performance springs and valves already which is interesting but I am getting all new everything anyways so it doesn't matter. Curious if getting the 2v heads fit for a 408 is even worth it or if I should just go with aluminum heads or something else for the price, it won't live in the high rpms most the time so I am not to concerned about the upper power band. In terms of HP, I am fine with making the lower end of what 408s put out, I don't need to maximize outputs at all. I will be assembling most of it myself outside of sending it out for machine work and head work.

This is what I have currently.
351c stock block: d2ae-ca, 3a3
2v heads: d1ae 2j27, d1ae 3a4
Factory 4 speed top loader
3.25 t-lok diff, think it needs a rebuild though I haven't cracked it open yet
Hooker comp headers, I can return or sell if I need a head swap.
Holley Sniper 2 EFI, wanted to try something different, seems the 2 unit has significantly better reviews than 1 which is why I considered it
Holley Hyperspark 2 distributor + ignition box
In terms of clearance, naca hood, power steering+brake, headers

Planning on a 2.5 inch dual exhaust all the way back with dynomax super turbos. Intake depends on what you guys advise, I was planning on a rpm performer air gap but that also depends on the opinion on the heads.

Lemme know if you guys want any more info or anything. I tinker with Pontiacs for the most part so all the ford stuff is new to me. Just want to get some input on my current idea, nothing is set in stone. Original plan was to just throw the engine back together stockish which is why I have a lot of these parts already but its out so I might as well just go for it.
Thanks.

Heads/piston pics for curiosity,
View attachment 88823View attachment 88824
Sounds like a good plan, only thing I would change is the heads. If you already have 2V headers and intake you can get the Edelbrock 61629 heads and get them ported. Unless you come across a set of closed chamber 4V heads that’s what I personally think would be the best option if you want some torque down low. Stay away from spending money on the 2V open chamber or 4V open chamber heads, they are prone to detonation.
 
Sounds like a good plan, only thing I would change is the heads. If you already have 2V headers and intake you can get the Edelbrock 61629 heads and get them ported. Unless you come across a set of closed chamber 4V heads that’s what I personally think would be the best option if you want some torque down low. Stay away from spending money on the 2V open chamber or 4V open chamber heads, they are prone to detonation.
Is the whole prone to detonation thing really valid? Seems the only time people were concerned about it was 20 years ago and now people say they run fine and the only positives of 4v is past 6k rpm.
 
Before you buy anything, find a VERY competent race engine machine shop that also has experience building 351Cs. Use the wrong machinist and parts selection won't matter much. The parts you select need to be "matched" to the rest of the drivetrain, as well as how the car will be used. A big cam, single plane intake, and a 3.25:1 gear will not play well together. Take advantage of the new technology in ring packages and cylinder wall finish honing. Insist on a deck plate being used to bore and hone. Given what I think I know, if using a stock Ford crank, use fully grooved main bearings even if you have to buy two sets to get there, the Boss 351 came with them for a reason (to save rod bearings on 2 and 7). Piston pin height should be selected so piston top is as close to zero deck as possible. If it ends up .020 or .030 down the hole, the compression loss will make it a dog in the low and mid-ranges as well as making it more prone to detonation/pre-ignition. Pay a bit more for a quasi-custom cam selected by someone VERY experienced with 351Cs. That person is NOT whoever answers the phone at Summit, Jegs, etc. Spend the money for quality valve train components. Be patient and don't get in a hurry. If you do, it will go slower and cost more.
Good luck with however you decide how to build the drivetrain. Chuck
 
Sounds like a good plan, only thing I would change is the heads. If you already have 2V headers and intake you can get the Edelbrock 61629 heads and get them ported. Unless you come across a set of closed chamber 4V heads that’s what I personally think would be the best option if you want some torque down low. Stay away from spending money on the 2V open chamber or 4V open chamber heads, they are prone to detonation.
 
My recommendation would be to use a wide ratio 4 speed top loader trans with the 3.25 rear.
Yeah, I believe my current 4 speed is a wide. Factory says it has a 3.25 rear with t-lok, but I havent cracked it open yet. As much as I like spinning tires in low gears I like being able to take it on the highway without it screaming, seems like 3.25 is the best for that.
 
Nice set up, how is the comp cams components working out for you? Was reading some forum posts saying they aren’t the best. I guess that is with everything though lol. Also any reason why you went over 60 and is it safe with a Cleveland?
No worries with CompCams... but then again, everybody has their preferences.

I went .060" over because the #4 & #8 were seized and rusted in-place since 1980-ish. Here's the view of #8 - the scar was so deep that .060" barely got rid of it.
engineteardown5.jpg

The engine runs like a champ, the temp gauge stays around 1/3 - even on days over 100. The perceived issues with Clevelands not surviving bigger bores applies primarily to racing scenarios... not simple cruising for fun. There's still plenty of meat between the cylinder walls.

enginereborn2.jpg

You don't need to mill the heads for adjustable rockers - the Crane Cams 7/16 screw-in studs work perfectly for that. Here they are with the CompCams Hi-Energy roller rockers and Edelbrock Performer intake:
intake1.jpg

The Edelbrock 1406 Performer carb, along with the big 7-blade fan & factory shroud, Duraspark ignition system (base idle timing @ 12*BTDC with the distributor curved for a 36*BTDC final timing) is an awesome package, IMHO. This set-up gets me burn-outs when I want them and I'm seeing somewhere around 19-20mpg, thanks to the OD in the '89 Mustang GT AOD transmission I swapped in with the original factory 3.00:1 rear gears (which is what was behind the '89 5.0, BTW).
engine1.jpg

I do have an Edelbrock E-Street TBI to swap in, but I'm working on my '80 CJ-7 right now - its AMC 304 has many of the same goodies I put into the Cleveland, although I went with Edelbrock's Pro-Flow 4 MPFI - this thing runs like a scalded dawg as well.
IMG_20231120_180259912.jpg

If only Edelbrock would've made a Pro Flow 4 for the Cleveland.

Rom air gap has a notch milled into the plenum to add a little single plane signal.

I would recommend it for the EFI.

Dual pattern cams will also help.

Make sure you get rid of the stock valves and mill the rocker pedestals for adjustable rockers.

I do have a set of heads with all the work done. I went aftermarket

Again, it's all about preferences, but mine's working just fine with the stock valves (3-angle job & hardened seats), a mild port & polish, mid-range roller cam, 1.73 roller rockers, Hooker Comp long-tube headers (get the ceramic-coated, they keep the heat down like nothing else), and the Pypes 2.5" stainless exhaust w/X-pipe.
 
No worries with CompCams... but then again, everybody has their preferences.

I went .060" over because the #4 & #8 were seized and rusted in-place since 1980-ish. Here's the view of #8 - the scar was so deep that .060" barely got rid of it.
View attachment 88841

The engine runs like a champ, the temp gauge stays around 1/3 - even on days over 100. The perceived issues with Clevelands not surviving bigger bores applies primarily to racing scenarios... not simple cruising for fun. There's still plenty of meat between the cylinder walls.

View attachment 88845

You don't need to mill the heads for adjustable rockers - the Crane Cams 7/16 screw-in studs work perfectly for that. Here they are with the CompCams Hi-Energy roller rockers and Edelbrock Performer intake:
View attachment 88842

The Edelbrock 1406 Performer carb, along with the big 7-blade fan & factory shroud, Duraspark ignition system (base idle timing @ 12*BTDC with the distributor curved for a 36*BTDC final timing) is an awesome package, IMHO. This set-up gets me burn-outs when I want them and I'm seeing somewhere around 19-20mpg, thanks to the OD in the '89 Mustang GT AOD transmission I swapped in with the original factory 3.00:1 rear gears (which is what was behind the '89 5.0, BTW).
View attachment 88843

I do have an Edelbrock E-Street TBI to swap in, but I'm working on my '80 CJ-7 right now - its AMC 304 has many of the same goodies I put into the Cleveland, although I went with Edelbrock's Pro-Flow 4 MPFI - this thing runs like a scalded dawg as well.
View attachment 88844

If only Edelbrock would've made a Pro Flow 4 for the Cleveland.



Again, it's all about preferences, but mine's working just fine with the stock valves (3-angle job & hardened seats), a mild port & polish, mid-range roller cam, 1.73 roller rockers, Hooker Comp long-tube headers (get the ceramic-coated, they keep the heat down like nothing else), and the Pypes 2.5" stainless exhaust w/X-pipe.
Thanks, I will definitely use some of this info for my own build, my block is significantly better looking than what you started out with so I’m even more confident now lol. The work you mentioned is on the stock 2v heads right, just wanna make sure? Thanks for the write up and pics, helps a lot.
 
My Pleasure!

Yes, stock 2V heads. The only new chunk of metal on that engine is the intake manifold (well, and the water pump... and headers). I didn't want to spend $2500+ on new heads that would've only really made a difference at track speeds. I just putt-putt around town and head out to a car show here and there, after all. I'm just happy the car is an actual car again after everything I had to do.

Good luck and have fun!
 
BTW, the Prothane captive 351 motor mounts do fit the 2v heads and exhaust manifolds (not 4v). They are a good safety feature and I have them on my 351c-2v.
Haven’t even delved into mounts or anything of the like yet, any reason for suggesting the propane ones? Also any clue on header clearance? Thanks, I just haven’t done much looking into accessories yet so I’m sort of in the dark.
 
Is the whole prone to detonation thing really valid? Seems the only time people were concerned about it was 20 years ago and now people say they run fine and the only positives of 4v is past 6k rpm.
It is all about the shape of the ignition chamber and how it leads to poor air flow during ignition. The open chamber heads allow the spark to ignite the fuel in a manner that causes poor ignition pattern. When you say it’s an old issue you are correct because nobody makes heads like that anymore.
If you use open chamber heads your engine will be restricted from meeting its peak performance either by reduced ignition timing or poor circulation of gases in the combustion chamber.
If you don’t believe me take a look at your open chamber heads. If you tried to squeeze more timing out of your engine before and experienced knock or ping that is something you simply can’t engineer out of the open chamber heads. Look at the dish of your heads and see if you have any small pock marks or divots in the surface of the head. That is pre-ignition destroying your heads.
You can argue changes in chemistry or high octane fuel all you want but the poor design leads to the flame front of your ignition event being allowed to dwell in the pocket of your head and miss the most powerful portion of the ignition stroke.
I am not bashing anyone’s ride I am simply stating that in an attempt to improve emissions reduction Ford made a mistake with the open chamber. Don’t dwell on it just correct it with better heads.
If you have the money go for 3V heads instead of the limiting 2V top end and the lagging 4V bottom end. I purchased all of the parts for my build during COVID when it was impossible to even get 3V heads.
My next project is a ‘68 Coupe and I will be building a period incorrect 3V 408 Stroker for that car. Just need to get the wife’s 73 out of the garage first.
 
It is all about the shape of the ignition chamber and how it leads to poor air flow during ignition. The open chamber heads allow the spark to ignite the fuel in a manner that causes poor ignition pattern. When you say it’s an old issue you are correct because nobody makes heads like that anymore.
If you use open chamber heads your engine will be restricted from meeting its peak performance either by reduced ignition timing or poor circulation of gases in the combustion chamber.
If you don’t believe me take a look at your open chamber heads. If you tried to squeeze more timing out of your engine before and experienced knock or ping that is something you simply can’t engineer out of the open chamber heads. Look at the dish of your heads and see if you have any small pock marks or divots in the surface of the head. That is pre-ignition destroying your heads.
You can argue changes in chemistry or high octane fuel all you want but the poor design leads to the flame front of your ignition event being allowed to dwell in the pocket of your head and miss the most powerful portion of the ignition stroke.
I am not bashing anyone’s ride I am simply stating that in an attempt to improve emissions reduction Ford made a mistake with the open chamber. Don’t dwell on it just correct it with better heads.
If you have the money go for 3V heads instead of the limiting 2V top end and the lagging 4V bottom end. I purchased all of the parts for my build during COVID when it was impossible to even get 3V heads.
My next project is a ‘68 Coupe and I will be building a period incorrect 3V 408 Stroker for that car. Just need to get the wife’s 73 out of the garage first.
I am sure the 3v heads are great, although pushing $4000 for a pair of bare heads at my door seems a little excessive. I am not trying to get max output or even high rpm performance, just a street car that'll hit WOT for smiles every once in a while. 4x4 has a similar build to what I am looking for, besides being a 351 vs 408, with the cast 2v heads and he seems to love it without any issues. By old issue I just meant people only complained about it 20 years ago, now when those same heads are put into use they seem to work great. Also, the last time this engine ran was before I was born so I can't say anything about how the heads performed unfortunately. I am by no means a Ford person or have extensive knowledge about them, I have tinkered with Pontiacs for the last couple years, but everything I know about Ford is just from extensive research and forum crawling. Thanks for the input.
 
In general the captive mounts are designed to hold the motor if the plastic or rubber insulator fails. The OEM mounts can split and allow the motor to move. This is a safety issue. The 73 OEM motor mounts were changed to address this safety concern. With the Prothane mounts, the 2v exhaust manifold clearance is minimal so headers will likely be a problem. See the attached pictures of my 351c 2v.
 

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