H-Code to 350HP, Drive Train and Suspension Help

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akherber

Well-known member
7173 Mustang Supporter Member
Joined
Nov 8, 2010
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Location
Choctaw, Oklahoma
My Car
1973 Mach 1
351c 2v
Edelbrock 4bbl, Performer Intake
Ram-Air
Pertronix Electronic Ignition
Ok, so I just finished reading months of posts on 351C upgrades and modifications and other schtuff. None seemed to really shoot for what I am looking to find out.

Firstly: Duchess is a 52500 mile 73 H-Code. She is un-restored and in very solid condition. The engine has never been opened (to my knowledge) and is reportedly stock. The only modifications are the Edelbrock performer intake and a 1406 600 carb.

So, I have decided even though the car is very complete and in great condition, a 73 H-Code is not going to sell for any amount that will build another 71-73 to my taste.

Lot's of questions here but I tried to keep them line item.

My vision is a 350 HP build. Something that wont get completely eaten off the line but is easy going enough to be my daily driver. Of course this will be hand-in-hand with a rebuild but what am I looking to do specifically to the engine to achieve this goal?

Should I replace my 2v heads with aussies or edelbrock aluminum or are they good enough for 350?

cams? (I understand what they do but not how to figure out what a better cam is)

pistons, valves? Id like to get good seats so I dont have to worry about unleaded fuel.

I really dont know where to point myself to build this engine up.

Longtube Headers? These are dependent on my choice in heads I believe. 2.5 inch H or X pipe the rest of the way back?

Functional Ram-Air. The idea is just cool to me and why not when I already have hood scoops. Id like to avoid intake/carb combos that will prevent this from becoming reality.

The rear end I'm guessing will be around 3.00 to facilitate highway driving. The FMX is a pretty heavy transmission and Id favor something both lighter and possibly with more than 3 gears. I'd like to be able to still perform at least as good as the FMX. Any suggestions?

I don't know where to replace or install a torque converter or do I need to.

Also, would anyone like to fill me in on the finer points of suspension? Not just the handling aspect but how the car rides and what I can do (kit, replacements, or rebuilds).

Interior and Exterior questions in good time.

 
That is alot of questions! haha

Longtube headers tend to have horrible ground clearance. If you have nice roads then this should not be a problem :) Mine hit constantly.

You dont like the fmx transmission? Alot of people dont give this tranny the credit it deserves. Had one in for yearssss with constant abuse and held up flawlessly.

 
Sounds like 350 is a good target. As far as the FMX, I'm no expert, but I've read on several sites that the C4 would handle that much HP and is a lot lighter. I'm sure you will get more input here on that.

 
if you want ram-air to work like factory i dont think you can have the aussie heads bc of the intake im going through that as we speak i have an rpm air gap and have been told it wont work untill i modofy the air cleaner housing, i did a full roller cam setup and a lot of other stuff check my garage and see, im in the 500hp range havent dynoed it yet but just ran the numbers through the comp cams camquest program and thats what it said 587 or something its a good program with a lot of options u might want to check that out on the com cam website and its free. the stock cleveland has very decent stock pistons at least mine does, i put 3.70 in my rearend with a detroit locker and moser 31 spline axels. but also put an AOD trans in it ie 4 speeds YAY. so i can run about 1800-2k going 70 on the high way saves on gas any questions on my build feel free to ask

 
I've not built any 2V cleveland engines (several 4Vs) but, I have looked into doing so a few times. The Australian closed chamber head flows no better than your open chamber head. The advantage is the closed chamber which reduces the probability of detonation and increases static compression for a given piston. The stock 2V intake port plateaus at about .425-.450 lift. With a 2.08 intake valve, a good valve job and minor "pocket porting" the intake will flow to about .500-.520 lift. Given the parameters you described, the aluminum heads seem to be more than you need and expensive. If a set of Australian heads can be purchased cheap enough they might be worth it for the reason stated above. Either way the stock valves should not be used, they break. Consider changing to an adjustable valve train, roller rockers and .080 wall thickness, hardened, custom length push rods. If you stay with bolt down roller rockers you will like need to get custom push rods as well. Choose a cam with lift numbers slightly larger than Int/Exh flow numbers. Keep static compression at about 9.0-9.25:1. Zero deck the block to further reduce the probability of detonation. Duration of about 220 @.050 and a lobe separation angle of 110. The idea on cam selection is support the engine's flow capabilities, vehicle's intended use, and end up with a Dynamic compression ratio that is compatible with the octane of the fuel being used. I do not think a split lift, split duration cam is needed for the 2V head. If the Ram Air permits try a 1" open spacer. You can use the existing Edelbrock intake if max RPM is about 5400-5700. The Hooker Comps fit well and primary pipe size is not too large. For what your goal is a 2.25" exhaust system is a better choice and creates more choices for tailpipes. I'd use the H pipe rather than X pipe (sound preference). Convertor selection is based on a lot of things (weight, gear, tire diameter, and torque curve) but, I'd guess that something that is similar in stall speed to the 71-73 351CJ convertor (about 2200-2400). I think the best first chassis improvement is weld on subframe connectors, especially convertibles. From there higher durometer rubber bushings, matched anti-roll bars, springs, modified lower control arms, etc. I hope this gives you enough information to help.

Chuck

 
What Chuck said X2.

I differ on exhaust; I'm not a fan of headers on a street driven car unless maximum performance is the goal. If you are going to run a full exhaust that is not obnoxiously loud stick with the manifolds. I do not believe headers offer much of an advantage with a street exhaust system. I also like the X pipe for efficiency, it helps smooth out pulses and helps scavenge the cylinders even with a full exhaust system and manifolds.

 
I've not built any 2V cleveland engines (several 4Vs) but, I have looked into doing so a few times. The Australian closed chamber head flows no better than your open chamber head. The advantage is the closed chamber which reduces the probability of detonation and increases static compression for a given piston. The stock 2V intake port plateaus at about .425-.450 lift. With a 2.08 intake valve, a good valve job and minor "pocket porting" the intake will flow to about .500-.520 lift. Given the parameters you described, the aluminum heads seem to be more than you need and expensive. If a set of Australian heads can be purchased cheap enough they might be worth it for the reason stated above. Either way the stock valves should not be used, they break. Consider changing to an adjustable valve train, roller rockers and .080 wall thickness, hardened, custom length push rods. If you stay with bolt down roller rockers you will like need to get custom push rods as well. Choose a cam with lift numbers slightly larger than Int/Exh flow numbers. Keep static compression at about 9.0-9.25:1. Zero deck the block to further reduce the probability of detonation. Duration of about 220 @.050 and a lobe separation angle of 110. The idea on cam selection is support the engine's flow capabilities, vehicle's intended use, and end up with a Dynamic compression ratio that is compatible with the octane of the fuel being used. I do not think a split lift, split duration cam is needed for the 2V head. If the Ram Air permits try a 1" open spacer. You can use the existing Edelbrock intake if max RPM is about 5400-5700. The Hooker Comps fit well and primary pipe size is not too large. For what your goal is a 2.25" exhaust system is a better choice and creates more choices for tailpipes. I'd use the H pipe rather than X pipe (sound preference). Convertor selection is based on a lot of things (weight, gear, tire diameter, and torque curve) but, I'd guess that something that is similar in stall speed to the 71-73 351CJ convertor (about 2200-2400). I think the best first chassis improvement is weld on subframe connectors, especially convertibles. From there higher durometer rubber bushings, matched anti-roll bars, springs, modified lower control arms, etc. I hope this gives you enough information to help.

Chuck
Click to expand...
wow i should have asked u a lot of questions b4 i built mine.... i did all the legwork on my own now i find theres help.... GREAT INFO


now im about to do pipes on mine... what the bid deal between x and h pipes just sound?

 
Last edited by a moderator:
I've not built any 2V cleveland engines (several 4Vs) but, I have looked into doing so a few times. The Australian closed chamber head flows no better than your open chamber head. The advantage is the closed chamber which reduces the probability of detonation and increases static compression for a given piston. The stock 2V intake port plateaus at about .425-.450 lift. With a 2.08 intake valve, a good valve job and minor "pocket porting" the intake will flow to about .500-.520 lift. Given the parameters you described, the aluminum heads seem to be more than you need and expensive. If a set of Australian heads can be purchased cheap enough they might be worth it for the reason stated above. Either way the stock valves should not be used, they break. Consider changing to an adjustable valve train, roller rockers and .080 wall thickness, hardened, custom length push rods. If you stay with bolt down roller rockers you will like need to get custom push rods as well. Choose a cam with lift numbers slightly larger than Int/Exh flow numbers. Keep static compression at about 9.0-9.25:1. Zero deck the block to further reduce the probability of detonation. Duration of about 220 @.050 and a lobe separation angle of 110. The idea on cam selection is support the engine's flow capabilities, vehicle's intended use, and end up with a Dynamic compression ratio that is compatible with the octane of the fuel being used. I do not think a split lift, split duration cam is needed for the 2V head. If the Ram Air permits try a 1" open spacer. You can use the existing Edelbrock intake if max RPM is about 5400-5700. The Hooker Comps fit well and primary pipe size is not too large. For what your goal is a 2.25" exhaust system is a better choice and creates more choices for tailpipes. I'd use the H pipe rather than X pipe (sound preference). Convertor selection is based on a lot of things (weight, gear, tire diameter, and torque curve) but, I'd guess that something that is similar in stall speed to the 71-73 351CJ convertor (about 2200-2400). I think the best first chassis improvement is weld on subframe connectors, especially convertibles. From there higher durometer rubber bushings, matched anti-roll bars, springs, modified lower control arms, etc. I hope this gives you enough information to help.

Chuck
Click to expand...
wow i should have asked u a lot of questions b4 i built mine.... i did all the legwork on my own now i find theres help.... GREAT INFO


now im about to do pipes on mine... what the bid deal between x and h pipes just sound?
Click to expand...
You can't go wrong by doing your own leg work, if you are thorough. And confirming the validity of others suggestions, myself included, is always advisable. You will find all sorts of discussions on the X vs. H subject. Most will advocate what they sell or have. The few dyno based comparisons I've seen indicate a small torque advantage for the H pipe below about 6000 RPM and a small HP advantage for the X pipe above about 6000. At exotic RPM (7500+) the power advantage of the X pipe probably becomes more pronounced. To me I like the H pipe on street Muscle Cars and X pipes on late model OHC engines. H seems to have more bass and rumble, the X seems to have more treble and raspy. Just a personal preference and opinion.

Chuck

 
I built my 351c with original block bored, balanced, stock crank, aussie heads with new valves and seats with screw in studs, roller cam, roller rockers, performer intake with 780 holley double pumper and sanderson shorty headers. Getting ready to start the motor in a couple of weeks. Shop that built my motor said the combination should make around 400 hp, we'll see. By the way converted from FMX to toploader, traction lock with 3.50 gears. Mark

 
Check out this forum that is specific to Clevelands

http://www.network54.com/Forum/119419/

350HP shouldn't be a problem.

While Ram air is 'cool' for all of your possible HP to cost options it will cost the most and benefit the least.

Put your money in the valve train. Go with the aussie or aftermarket heads (aluminum would reduce weight over the front end and help with handling). The small CC will raise compression and give you more bang for the buck. Roller rockers will reduce internal drag but can be a little pricey. I think the Cleveland guys will tell you the Clevelands like split duration cams and improved exhaust (headers). I would go with roller hydro cam, roller rockers, stainless valves with matched valve springs. You won't be turning it more than 5000 or so RPM so focus on torque and having the torque come in early.

If you replace the FMX go with something that has an overdrive rather than another three speed. Any extra weight you might gain (I don't know if most OD tranny's are heavier than a c4) you can offset by higher rear end gears. You could get away with 3.73 or higher depending on how much highway driving you do. Nothing will get you moving faster than higher rear end gears.

 
Ok so I'm learning engines. Hydraulic Cams activate the rockers using Hydraulic Lifters, Mechanical using pushrods. Cams are roller or not referring to the type of tappet used. Question: Why does it matter if the cam is hydraulic or not? Seems like the real change is after the tappet...

So anything on the valve train can be changed and worked on without pulling the block out, just the heads? Better yet, I could buy the heads I plan on using, the rockers, valves, springs, lifters and the cam set up, and put it all together and in a day be able to swap it all out? or maybe over a weekend?

Decking and any boring that needs to be done is machine shop and can wait?

Exhaust that fits on the 2V heads will fit Aussie 2V heads and aftermarket 2V heads? It seems logical that it would but I'm not looking to make an expensive mistake.

 
Basically for your engine there are 4 type of lifters:

Solid flat

Hyd flat (Typical installation uses these)

Solid Roller

Hyd Roller

Solid lifters of either type require occassional adjustment or checking of the valve train.

Hydraulic don't.

All things being equal you can get more RPM's out of a solid lifter since it doesn't rely on having pressurized fluid in it.

Roller vs flat cams.

The lifters ride on the camshaft. Flat lifters are just that, they are flat on the bottom while roller lifters have a little roller on them like a wheel.

One big advantage of a roller lifter over a flat lifter is the 'ramp' of the cam can be 'faster'. This means you can get more lift with less overlap. You also don't have to 'break in' a roller cam. Now, Clevelands didn't have them stock so it's an after market kit and it isn't cheap but I think it is the way to go.

All four use push rods to connect to the rocker arms. The rocker arms transfer the energy down onto the valve.

Rocker arms come in both adjustable and non-adjustable as well as fulcrum and roller style. Stock is fulcrum. Rollers have the advantage of less friction and more accurate operation. Mechanical lifters of either type (flat or roller) require an adjustable rocker arm. Hydraulic don't but you can use them.

As a general rule you can do all valve train work without pulling the block. This includes swapping cams. It is very popular to do just like you suggested, get the heads all done and then swap them out in a weekend (or a couple of extra days if you have not done it before). Oh, and as a bonus, the cleveland is a 'dry' manifold meaning the intake doesn't have any coolant in it. It's a lot less messy....

You can deck the heads a little but yes, decking the block/boring will need the engine out of the car. With the HP numbers you are looking at you probably don't need to do any lower end work.

You need to do your homework before actually purchasing an aftermarket head to make sure you understand what will and won't work with it. The aussie heads will work with 2v manifolds (both intake and exhaust)

 
Last edited by a moderator:

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