Vote 428 or aluminum 427FE??

[RodKnock]

All this engine talk is making me anxious to build another engine. Please stop.

Nothwithstanding, the block will be either a Pond or CSX aluminum block.

[elmariachi]

Originally Posted by RodKnock

All this engine talk is making me anxious to build another engine. Please stop. Nothwithstanding, the block will be either a Pond or CSX aluminum block.

What a fitting post. Jamo should probably lock this thread right here and now.

[RodKnock]

Well, I for one would like to know what will eventually grace the engine compartment of the Ironman Kirkham.

Resto, have you purchased a block yet?

[Excaliber]

Rodknock, I know!!! I can hardly wait for my engine to blow so I can get in there and make some more mods.

[RodKnock]

Originally Posted by Excaliber

Rodknock, I know!!! I can hardly wait for my engine to blow so I can get in there and make some more mods.

It's a double-edged sword and a slippery slope, but like most, I do enjoy the "build" portion of ownership. You always learn things the first time around that you would employ in your next build.

I think Resto is asking the right questions and should have himself a fine Cobra when done.

[patrickt]

Originally Posted by RodKnock

... but like most, I do enjoy the "build" portion of ownership.

We need to get you to branch out in to the "repair" portion of ownership.

[RodKnock]

Originally Posted by patrickt

We need to get you to branch out in to the "repair" portion of ownership.

Like most, if not all, I'm time challenged. Also, the car has been mostly problem-free (knock on wood). I had an electrical issue sorted out a few months back by a professional, since wiring and me do not get along together.

[patrickt]

Originally Posted by RodKnock

Like most, if not all, I'm time challenged. Also, the car has been mostly problem-free (knock on wood). I had an electrical issue sorted out a few months back by a professional, since wiring and me do not get along together.

Was that why you dumped your MSD Distributor?

[dcdoug]

My repro of the Shelby sales literature shows that the street cars were rated by Shelby at 425HP and the comp cars at 480HP. Probably more realistic as the comp cars were modified. The repro info could be fabricated, but doesn't seem to be.

[Excaliber]

Hmmm, good question about the alloy heads. I thought only a FEW of the comp cars got them, not all of them? For Le Man's I believe Shelby went with a iron high riser head. I wonder which was the better head, alloy of that time or iron high riser? Of course the alloy heads had a weight advantage.

"American Muscle Car" had a show about legend vs reality where they had a shop assemble a number of old school engines using only stock parts that were available when engines were on the street. No modifications were allowed with the exception of an .060 overbore. The FE 427 was probably lucky to get half that for an overbore. Here are the results, the HEMI is particularly note worthy, rated by Chrysler at 425 horse. Uh huh, and pigs fly!

The Chevy 409/409 ..........................406 HP
The Ford 427/425 Tunnel Port..............637 HP
The Pontiac 421/421 SD......................488 HP
The Chrysler 426/425 Street Hemi.........820 HP
The Chevy 427/430 L-88......................527 HP

[RodKnock]

Originally Posted by Excaliber

Hmmm, good question about the alloy heads. I thought only a FEW of the comp cars got them, not all of them? For Le Man's I believe Shelby went with a iron high riser head. I wonder which was the better head, alloy of that time or iron high riser? Of course the alloy heads had a weight advantage.

"American Muscle Car" had a show about legend vs reality where they had a shop assemble a number of old school engines using only stock parts that were available when engines were on the street. No modifications were allowed with the exception of an .060 overbore. The FE 427 was probably lucky to get half that for an overbore. Here are the results, the HEMI is particularly note worthy, rated by Chrysler at 425 horse. Uh huh, and pigs fly!

The Chevy 409/409 ..........................406 HP
The Ford 427/425 Tunnel Port..............637 HP
The Pontiac 421/421 SD......................488 HP
The Chrysler 426/425 Street Hemi.........820 HP
The Chevy 427/430 L-88......................527 HP

Well, at least the L88 is believable.

[dcdoug]

This should be a fun conversation. I am going to go and get some popcorn.

[Excaliber]

Actually, as I mentioned earlier, THAT version of the engine had one very important modern part. The solid roller cam from hell that didn't even begin to make power until about 3,000 rpm.

90 plus horse power loss with the side pipes.

[RodKnock]

Prior to moving up to a bigger engine, I installed a crate Chevy LS6 454/450 engine in my old Corvette. That was a very honest HP figure. A set of AFR heads made it about 500 HP and then I went to crate 540 ci engine that made 600+ HP. All dyno'ed on two different dynos.

I have a hard time believing a stock HP Ford head is equal to a stock HP Chevy head, but what do I know. I'm no expert.

[Excaliber]

Rodknock, most of those GM crate motors make their power from a low rpm roller cam, 5,200-5,500 rpm, in that range. Old school tech was based primarily on high rpm, thats a whole different setup for the heads, intake, etc.

[RodKnock]

Originally Posted by Excaliber

Rodknock, most of those GM crate motors make their power from a low rpm roller cam, 5,200-5,500 rpm, in that range. Old school tech was based primarily on high rpm, thats a whole different setup for the heads, intake, etc.

The original HP crate engines available from Chevy during the 1970's, 1980's and 1990's, such as the L88, LS6 and LS7 has solid flat tappets installed. Rollers were not widely available then.

Obviously, the newest offerings are now roller cam engines.

[Excaliber]

Rodknock says,,,

I have a hard time believing a stock HP Ford head is equal to a stock HP Chevy head...

That would seem logical, considering the porkupine valve train layout, large oval style ports, etc. So I did just a quick and brief cfm flow check for various GM heads, including after market such as AFR. I like to compare flow data at 500 lift, so anytime I speak of cfm flow, thats my base line.

Surprisingly, GM heads are not all that great compared to the High Riser, not even the Tunnel ports, of Ford. In general it appears they flow about the same or LESS than stock High Riser heads, again, at 500 lift. I would have agreed with Rodknock initially on this, I would have assumed the big block Chev heads would easily outflow the big block Ford heads. Doesn't seem to be the case.

Also, it appears that making in excess of 500 horse with flow well below 300 cfm is certainly do-able. In fact, by the time you get to 300 cfm, or near it, those are some bad ass heads!

The reason I like to use 500 lift, maybe 600 lift, is because I have a "hunch" that is representative of a more typical street type application. Few street cars have a lift that exceeds 600, again, just a hunch. Flow data is a lot like dyno numbers, so many variables you do have to take it with a grain of salt, not hard data. Unless those variables are carefully spelled out.

[RodKnock]

Originally Posted by Excaliber

Rodknock says,,,


That would seem logical, considering the porkupine valve train layout, large oval style ports, etc. So I did just a quick and brief cfm flow check for various GM heads, including after market such as AFR. I like to compare flow data at 500 lift, so anytime I speak of cfm flow, thats my base line.

Surprisingly, GM heads are not all that great compared to the High Riser, not even the Tunnel ports, of Ford. In general it appears they flow about the same or LESS than stock High Riser heads, again, at 500 lift. I would have agreed with Rodknock initially on this, I would have assumed the big block Chev heads would easily outflow the big block Ford heads. Doesn't seem to be the case.

Also, it appears that making in excess of 500 horse with flow well below 300 cfm is certainly do-able. In fact, by the time you get to 300 cfm, or near it, those are some bad ass heads!

The reason I like to use 500 lift, maybe 600 lift, is because I have a "hunch" that is representative of a more typical street type application. Few street cars have a lift that exceeds 600, again, just a hunch. Flow data is a lot like dyno numbers, so many variables you do have to take it with a grain of salt, not hard data. Unless those variables are carefully spelled out.

Sorry, I don't believe you. Please specify which GM heads you flowed. First, most HP solid lifter cams from GM had more than .500 lift. Second, the square port (not the weaker oval port) heads are the high performance heads in the GM lineup. Third, there's no way a Ford high rise or tunnelport head outflowed a modern BBC AFR head (they have many from small to large cc's).

I would need to see data all the way through the lift range to believe you.

[RodKnock]

Here are the AFR BBC heads from very small to very large:

http://www.airflowresearch.com/index.php?cPath=68

[Excaliber]

I don't see the problem with my earlier post about the flow rates. According to the link you just posted, Rod, the average flow rate for AFR, Brodix, E-Brock, GM iron heads and many others range from a low of 240 to a high of 293. That average is based on lift amounts up to 800.

That data is consistent, in general terms as to my previous post, that any head that flows 300 or better is a terrific head. Stock big block GM heads, surprisingly, aren't significantly better than big block Ford heads.

If were comparing modern heads, like AFR, the Blue Thunder FE heads, "worked" flow 350-400 cfm.

Avg. Flow
298 276 270 262 266 247 240 270 262 273 260 263 278 275 276 272 293