2v engine setup

[Wolverine]

Wolverine, I'd be interested in checking out your engine build spreadsheet. My M-code engine is slated for rebuild at some undetermined point in the future. I think I'll add Spintech mufflers to the list as a consideration as well.

Cool...I will see if I can email to you as an Excel attachment....stay tuned.

 

[Totalled]

Unless you can source complete 4V heads at a decent cost... I think I'd order up a set of trick flow aluminum heads and call it a day.

I purchased and rebuilt a set of closed chamber 4V heads to replace my open chambers... I'm within spitting distance of the cost of the TFS or Edelbrock heads..

Next step for me is a set of CHIs.

 

[Tnfastbk]

Unless you can source complete 4V heads at a decent cost... I think I'd order up a set of trick flow aluminum heads and call it a day.

I purchased and rebuilt a set of closed chamber 4V heads to replace my open chambers... I'm within spitting distance of the cost of the TFS or Edelbrock heads..

Next step for me is a set of CHIs.

Just go for the AFD's

http://www.airflowdynamics.com.au/site_flash/products/cleveland_heads.htm

 

[mus72]

I'll throw my build in comp cams 280 2v heads with 4v valves the bit that everyone forgets is you can't compare properly unless you use the same carb,gears, stall, compresion ratio ,air filter and exhaust etc and like has been said if you're going to do a major head rebuild it makes sense to put on a set of alloy ones which are essentailly 3vs .

Don't forget if you upgrade the cam etc you might have to change the converter and gears to make it work properly when I rang comps tech line they wanted to know what carb and gears I was running so I rang Holley to see what they recommended they wanted to know what cam I was running so what comes first the chicken or the egg?

My advice build what you can afford to finish momenteum quickly drops off and everything starts to become I'll do that tomorrow , there again its probably only me.

 

[Wolverine]

My advice build what you can afford to finish momenteum quickly drops off and everything starts to become I'll do that tomorrow , there again its probably only me.

My rule of thumb...for every hour of disassembly, a day of assembly is incurred running down replacement parts, cleaning, documenting what I did, and installing.

Based on posts I have read here, as well as other member posts, it doesn't seem there is a need to purchase after market heads for performance.

It seems to me there are several factors one considers when purchasing heads, each based with different priorities based on owner/builder tastes/$$$.

**There is the wow factor...which almost got me to fork over big $$$ for a beautiful shiny pair of aftermarket heads.

**There is the price/availability factor...I found a 71 351C block with 4v quench heads, crank and stock manifold(none touched from stock) for $450. If my car wasn't a 302, but a 351C 2V, I probably would have just used that, unless I got a cheap pair of 4v quench heads.

**There is the performance factor... and several posts indicate they have 2V heads that perform at least as well as 4V.

**There is the vintage factor...I like to use stock, limited availability parts where possible for bragging(I know that is hard to believe).

**There is the pump gas factor...here you have to decide who to believe. I was convinced quench heads will run better on pump gas then open chamber.

Any other factors?

You guys that run 2V, do you increase your valve diameter to match the 4V, or do you leave that alone? My book indicates on intake, 2v= 2.040 4V= 2.191, exhaust 2V=1.665, 4v=1.710. On the surface, doesn't look like much of a difference.

 

[M Beauchamp]

What is the difference between:

4v Closed chamber



and 4v open chamber

 

[c9zx]

My advice build what you can afford to finish momenteum quickly drops off and everything starts to become I'll do that tomorrow , there again its probably only me.

My rule of thumb...for every hour of disassembly, a day of assembly is incurred running down replacement parts, cleaning, documenting what I did, and installing.

Based on posts I have read here, as well as other member posts, it doesn't seem there is a need to purchase after market heads for performance.

It seems to me there are several factors one considers when purchasing heads, each based with different priorities based on owner/builder tastes/$$$.

**There is the wow factor...which almost got me to fork over big $$$ for a beautiful shiny pair of aftermarket heads.

**There is the price/availability factor...I found a 71 351C block with 4v quench heads, crank and stock manifold(none touched from stock) for $450. If my car wasn't a 302, but a 351C 2V, I probably would have just used that, unless I got a cheap pair of 4v quench heads.

**There is the performance factor... and several posts indicate they have 2V heads that perform at least as well as 4V.

**There is the vintage factor...I like to use stock, limited availability parts where possible for bragging(I know that is hard to believe).

**There is the pump gas factor...here you have to decide who to believe. I was convinced quench heads will run better on pump gas then open chamber.

Any other factors?

You guys that run 2V, do you increase your valve diameter to match the 4V, or do you leave that alone? My book indicates on intake, 2v= 2.040 4V= 2.191, exhaust 2V=1.665, 4v=1.710. On the surface, doesn't look like much of a difference.

"**There is the performance factor... and several posts indicate they have 2V heads that perform at least as well as 4V. "

Some may have indicated that but, I've yet to see it on the street, on the track, or on the dyno. That is not to say 2V heads can not be made to work well. However, with the same level of effort (and money) in a 2V and a 4V head, the 4V will always build significantly more power. This 4V is too big for the street thing got started a very LONG time ago by cam grinders (and Chevrolet Racers )who didn't understand why their Windsor based cams didn't work well in 351C 4Vs, and still persists. I suppose if a person wanted to run a 2.75 gear in a 3700 lb vehicle, limit RPM to 4600, and was looking for the best mileage the 2v certainly would be more "streetable' than the 4V. Chuck

 

[73vertproject]

I always try to (usually foolishly) understand the "why" factor, which my biochem teacher called "teleological thinking". The only reason I mention that is to honor his memory.

So, why would Ford design both 2 venturi and 4 venturi heads? The easy answer is that is the 2V had better fuel efficiency than the 4V. The trade-off? Performance of course.

Aftermarket manipulation of the cam, intake, carb, exhaust, etc. affects the performance differences associated with the heads. The larger sizes of the intake and exhaust ports on the 4V heads is aligned with the power increases available with the 4V, especially at higher RPM. I haven't come across any article that describes the 2V (which are in my 'vert) heads being used in racing back in the early '70s. If you know of such a document, please share it.

My nickel's worth,

Doc

 

[Wolverine]

I haven't come across any article that describes the 2V (which are in my 'vert) heads being used in racing back in the early '70s. If you know of such a document, please share it.

Doc

Personally, I am inclined to take DROPTOP's 2V words from an earlier post. He changed my position on this issue...if I had 2V heads and couldn't get a set of 4V Quench for a good price(whatever that means, probably $100), I would build with my 2V heads and be confident in performance. That is because I am confident based on Droptop's numbers.

Granted, he is racing, and I am driving to the grocery store...ok liquor store, but he seems pretty adamant. I am sure he has taken more motors apart that I have removed spark plugs.

But if I did put it together, and my car wasn't loud and didn't go go go...


Also, I will add this:

351C Head Identification

Head/ Type/ Chamber Volume/ Identification/ Application

US 4V CLOSED 61.3-64.3cc 4 cast in corner

US 4V OPEN 76.9-79.9cc 4 cast in corner

US 4V CLOSED 64.6-67.6cc 4 & dot cast in corner

US 2V OPEN 76.9-79.9cc 2 cast in corner

OZ 2V OPEN 72.2-75.2cc None 351 XA on

OZ 2V CLOSED 56.4-59.4cc None 302 All"

 

[Totalled]

Just go for the AFD's

http://www.airflowdynamics.com.au/site_flash/products/cleveland_heads.htm

Why do you prefer those to the CHIs? I was looking at the CHI 4V.

http://www.chiheads.com.au/4v_228cc.php

 

[Tnfastbk]

Just go for the AFD's

http://www.airflowdynamics.com.au/site_flash/products/cleveland_heads.htm

Why do you prefer those to the CHIs? I was looking at the CHI 4V.

http://www.chiheads.com.au/4v_228cc.php

No preferance, it just depends on who you talk to which is better. I went with these because I liked what I saw and the quality is top notch. But like I said on the 351 forum Chi seems to be the boss for some. I think they both come out of Australia so truth be known they are prob linked some how. In my post above it gives all the flow numbers and such.

 

[mus72]

My advice build what you can afford to finish momenteum quickly drops off and everything starts to become I'll do that tomorrow , there again its probably only me.

My rule of thumb...for every hour of disassembly, a day of assembly is incurred running down replacement parts, cleaning, documenting what I did, and installing.

Based on posts I have read here, as well as other member posts, it doesn't seem there is a need to purchase after market heads for performance.

It seems to me there are several factors one considers when purchasing heads, each based with different priorities based on owner/builder tastes/$$$.

**There is the wow factor...which almost got me to fork over big $$$ for a beautiful shiny pair of aftermarket heads.

**There is the price/availability factor...I found a 71 351C block with 4v quench heads, crank and stock manifold(none touched from stock) for $450. If my car wasn't a 302, but a 351C 2V, I probably would have just used that, unless I got a cheap pair of 4v quench heads.

**There is the performance factor... and several posts indicate they have 2V heads that perform at least as well as 4V.

**There is the vintage factor...I like to use stock, limited availability parts where possible for bragging(I know that is hard to believe).

**There is the pump gas factor...here you have to decide who to believe. I was convinced quench heads will run better on pump gas then open chamber.

Any other factors?

You guys that run 2V, do you increase your valve diameter to match the 4V, or do you leave that alone? My book indicates on intake, 2v= 2.040 4V= 2.191, exhaust 2V=1.665, 4v=1.710. On the surface, doesn't look like much of a difference.

The wow factor? not really the cost of skimming a used head ,new valve guides ,porting etc plus purchase cost soon adds up never mind the fact that most new heads are a combination betwen the 2v and 4v and flow real well, it takes hours to port one of these heads properly and when your done they will still be a lot heavier.

The 4v valves are bigger and a little time spent on the vavles themselves will help them flow the 4v ports are huge I have a set of both if I I personally think the 2vs well ported would give better low end torque the 4v would come in more over 4000rpm .

I would also have thought the open chambered suited low quality petrol as the quench heads are higher compression (probably wrong there) .

0

 

[marks73]

Or just send your check book and Jeff, Doc, Mark and myself will take care of the rest

Been watching this pan out with great delight because I've done both.

Rule #1. If your expecting ABC Sports helicopter at finish line with a $6,000,000 check with your name on it. We can do that. (kinda costley)

Rule #2. If your looking to NEVER loose a street race. (see Rule #1 )

Want to put a smile on your face with what budget you can live with?

Just tell us how fast for how far and do you intend to drive it over long distance trips.

We'll set you right up

 

[Wolverine]

The wow factor? not really the cost of skimming a used head ,new valve guides ,porting etc plus purchase cost soon adds up never mind the fact that most new heads are a combination betwen the 2v and 4v and flow real well, it takes hours to port one of these heads properly and when your done they will still be a lot heavier.

The 4v valves are bigger and a little time spent on the vavles themselves will help them flow the 4v ports are huge I have a set of both if I I personally think the 2vs well ported would give better low end torque the 4v would come in more over 4000rpm .

I would also have thought the open chambered suited low quality petrol as the quench heads are higher compression (probably wrong there) .

I paid $450 for a used block, crank, head, intake manifold. To machine my heads, replace the valves and put in springs cost me $300. I don't see how the costs add up to new heads. I show Edelbrock head at $1300/pair vs $750 used...and I have valuable parts left over. I am going to spend that money on a choice pair of headers.

Can't argue with the weight issue....but I will have nice headers! If I was looking to shave a few hundredths off of my ET's, that might help.

My understanding (and I will find out first hand) is HIGH COMPRESSION with open chamber heads is more likely to detonate then HIGH COMPRESSION with closed/quench chambers. I will let you know in June, as I will be running a STOCK COMPRESSION(10.5) quench. I imagine low compression either way is a wash, though I don't know if you can get a low compression piston for a quench head.

 

[droptop73]

The debate on 4v vs 2v will rage on! Port and valve sizing on the 4v heads is more suitable to either much higher valve lifts or greater displacements to be used effectively. For all out performance the 4v head definately holds an advantage. You simply cannot get a "line of sight" to the intake valve in the 2v head like you can in a 4v. The flow in 4v ports when used on a stock displacement engine have dead air spots, the 2v has better flow velocities but has to turn sharper corners. It's all give and take. To me the 2v heads are more appealing on a street engine due to the better velocities. If you compare the 2v head to any production SBC head it is miles ahead.

My 2v heads are slightly modified with bronze valve guide liners, hard exhaust seats, roller rockers, guide plates and screw in studs. I smoothed out the valve pocket and streamlined the valve guide area. The ports were left stock sized with just the hiccups cleaned up. The valves are cut down 4v one piece stainless @ 2.060 intake and 1.655 exhaust. I don't have any flow numbers or real performance numbers since I do not intend to race the car. What I do know is it needs more rear gear although with the 5 speed and a 3.35 low gear it should accelerate better. I am very fortunate to have access to the equipment to have performed this work myself.

As for open vs closed (quench) chambers is the closed portions of a closed chamber head causes turbulence or "squish" in the cylinder which makes it more resistant to detonation. It is harder to control flame travel in the open chamber head. Current technology is "mirrored" chambers which have a smaller closed chamber and a mirror image dish in the piston. Pretty cool stuff!

 

[M Beauchamp]

There is some very cool stuff here.

This all helps understand the performance issues.

so it fair to say that the 2v head have pinning issues that can be improved but not eliminated

the 2v Aussie head are super and best of both world?

the 4v open chamber are good for today fuel better that 2V

the 4v closed are best for high HP builds better then 4v open

I have found some 4v open for 100-150, i would think that the rebuild cost is similar 2v or 4v

would this be a good path forward.

 

[Don65Stang]

As for open vs closed (quench) chambers is the closed portions of a closed chamber head causes turbulence or "squish" in the cylinder which makes it more resistant to detonation.

I didn't know this. Cool.

Group question: Given a stock engine what octane at gas stations should we use for:

4V closed heads?

4V open heads?

2V heads?

(because I have all three...but not all in running condition at the moment)

 

[guys72Mach1]

After dumping tons of time and cash into my engine, just so I can put the pummeling on some bow tie at will,(and put a smile on my face) I just can't bring myself to put 87 octane in the tank to save $5.15. Just the off chance that it may ping at 6,500 gives me the willies and makes me feel all cheap and dirty, like I need to go shower and get some counseling...

but that's just me...

 

[c9zx]

The debate on 4v vs 2v will rage on! Port and valve sizing on the 4v heads is more suitable to either much higher valve lifts or greater displacements to be used effectively. For all out performance the 4v head definately holds an advantage. You simply cannot get a "line of sight" to the intake valve in the 2v head like you can in a 4v. The flow in 4v ports when used on a stock displacement engine have dead air spots, the 2v has better flow velocities but has to turn sharper corners. It's all give and take. To me the 2v heads are more appealing on a street engine due to the better velocities. If you compare the 2v head to any production SBC head it is miles ahead.

My 2v heads are slightly modified with bronze valve guide liners, hard exhaust seats, roller rockers, guide plates and screw in studs. I smoothed out the valve pocket and streamlined the valve guide area. The ports were left stock sized with just the hiccups cleaned up. The valves are cut down 4v one piece stainless @ 2.060 intake and 1.655 exhaust. I don't have any flow numbers or real performance numbers since I do not intend to race the car. What I do know is it needs more rear gear although with the 5 speed and a 3.35 low gear it should accelerate better. I am very fortunate to have access to the equipment to have performed this work myself.

As for open vs closed (quench) chambers is the closed portions of a closed chamber head causes turbulence or "squish" in the cylinder which makes it more resistant to detonation. It is harder to control flame travel in the open chamber head. Current technology is "mirrored" chambers which have a smaller closed chamber and a mirror image dish in the piston. Pretty cool stuff!

Droptop is on the money. The placement of the port on 4v is much higher in the head giving the straight shot to the valve. The bottom.250-.300 of the intake port is very low velocity "dead space" which is why the flow improve when the bottom of the port is filled or "stuffed". The flame travel and complete burn is the issue the greater the distance and the greater the volume the more difficult it is to get a complete burn so that there is little unburnt mixture to be ignited by a hot spot when you don't want it to. Keeping the top of the piston closer to the top of the block deck decreases the volume and distance the flame has to travel and lessens the chance of detonation. Production practices were to leave the piston "down the hole" a bit to control static compression ratios. If you zero deck the block the piston top is even with the top of the block and the distance and volume is decreased and swirl is increased. As droptop said the latest technology is the mirrored chamber in a small figure 8 shape. Diamond Pistons does a lot of this and it works, but is not cheap. Chuck

There is some very cool stuff here.

This all helps understand the performance issues.

so it fair to say that the 2v head have pinning issues that can be improved but not eliminated

the 2v Aussie head are super and best of both world?

the 4v open chamber are good for today fuel better that 2V

the 4v closed are best for high HP builds better then 4v open

I have found some 4v open for 100-150, i would think that the rebuild cost is similar 2v or 4v

would this be a good path forward.

I don't feel the Aussie CC 2V head is worth the cost, it flows no better than the American OC 2V head. All these heads can be used with todays fuel if the block is zero decked, Static Compression Ratio (SCR) held to 9.5:1 (for iron heads), Dynamic Compression Ratio (DCR held to 7.6-8.0:1, detonation is much less likely to occur with any of the heads on 91 Octane pump gas. SCR is fixed by the volumes of the chamber, piston, head gasket, and placement of the top ring land. The timing events of the camshaft are used to control the DCR, the later the intake valve closes the lower the DCR. In my opinion the smaller chamber of the CC head is better for high HP use simply because you can get higher SCR without using a domed piston that impedes flame propagation. As to is it a good path forward, again it comes down to what do you want it to do and how much do you want to spend. If you want the power and can live with, at the minimum, a 3.25 gear the OC 4V at $150 is a reasonably good deal. No matter what you decide the machinist is the wildcard. A poor one can make the build a big disappointment and you'll never know why "it just doesn't run as good as it should". Chuck

After dumping tons of time and cash into my engine, just so I can put the pummeling on some bow tie at will,(and put a smile on my face) I just can't bring myself to put 87 octane in the tank to save $5.15. Just the off chance that it may ping at 6,500 gives me the willies and makes me feel all cheap and dirty, like I need to go shower and get some counseling...

but that's just me...

You are exactly right, it is cheap insurance. You should feel cheap and dirty for having those thoughts. And I think it will take more than one session with the counselor. Chuck

 

[droptop73]

I do want to emphasize, I am in no way saying and would not say the 2v head is better than the 4v head. I do however think there are many applications where OVERALL performance can be enhanced by that option. By overall performance I mean average driving any car will normally see, fuel economy and enough power to "get into trouble" (take that however you will). I have been running around with some very dedicated Ford guys for a long time. I've seen a few street cars with 2v heads run well into the 12s in the quarter. That said the E/S '72 "R" code Mustang (the cars not a real "R") my friend races has gone a 10.82 @ Indy.

Like Chuck says it's a total combination. I've seen too many guys spend too much money to go slow>