Cylinder Heads?

[jerrysta]

Guys, I need some help in picking cylinder heads. I need to know if they need to be LT1 specific or if they can be any chevy 350 heads. Can anyone let me know?

Thanks.

[98z28thompson]

yes they need to be lt1 specific. they are reverse flow heads.

[jerrysta]

Has anyone used the Trick Flow heads? AFR's are too much money and I fear that the LT4 heads may not be able to be worked we enough for my application.

THe specs are 195cc intake 75cc exhaust 62cc combustion chambers.

This will be a big stroker when we're done and these heads claim they are for stroker apps.

I would maybe consider the AFR heads but they seem to be way too pricey for what I want to spend. Is there another head I should consider?

Anyone know about the Trick Flow heads?

[soCalTA]

why dont you rework the heads you have?

[jerrysta]

I'm going with a big stroker application and whatever heads I get will be "worked" a bit by the builder. At the very least I may get LT4 heads since, when ported, they will outflow LT1 ported heads.

I don't have data on the flow numbers exactly, but I don't want to give up HP by skimping on the heads. If I can start with a better head at not a great expense more than that's what I want to try to do. I am leaning away from the LT4 heads, though, because they only come assembled. He is going to save me money by buying the heads bare as he gets a discount on most parts from a large group of aftermarket companies.

So, if anyone knows the flow data on the LT1 heads that mey help, but I'm pretty sure that the LT4 heads when ported will be better and I am exploring the other options I may have in an aftermarket head.

[Injuneer]

Some random thoughts.....

People are pushing the LT1 castings to 300cfm. The LT4's can flow more than that.

AI has done a 300+ Twisted Flow head. Downside to the TF head is the over-size combustion chamber - 62cc. That means you either have to mill the heads or maybe use a domed piston to get a decent compression ratio. They are advertised as "blower" heads for that reason.

The AFR's are "OK" but typiclly need a lot of additional work after they come out of the box.

But head flow is not all about "cfm"..... there are people out there who, using the correct head and cam design, can get the kind of HP that you are looking for with heads that flow under 300cfm.

The problem with most of the aftermarket "LT1/LT4" heads is that to design the head, they started with a Gen 1 SBC head, and moved the cooling passage holes. Cheapest way to come up with a "new design". Problem is most Gen 1 SBC heads were designed with large combustion chambers (65cc) because people generally didn't push the compression ratio like they do today. So, to get the required 54cc chambers for the typical LT1/LT4 build, they just added some metal to the top of the chamber, sinking the spark plug into a hole, and increasing valve shrouding.

Big AFRs are for track cars. They have large intake runners = low velocity at low rpm, and are all "top end"..... not for a street car that needs some decent torque down low.

If you want a really huge heads, you get one of the aftermarket SBC heads like the Brodix or the SBC2.2 heads and convert them to reverse flow cooling. I have seen people claiming ~380cfm with the SBC2.2 heads.

[94Z/28]

If you are looking to compare flow numbers carcraft.com has a cylinder head database with info on a lot of small block heads.

[jerrysta]

The guy doing the motor can work the heads. I guess what we're looking for is potential.

Fred, as always your post was very informative. Did you mean "trick flow" when you posted "twisted flow"? Or is that a different brand?

Thanks. I hope you meant trick flow because I don't have to break the bank to get them.

[Injuneer]

I meant Trick Flow.... but "Trick Flow" tries to sell the concept of "twisted flow" as the design feature of their heads. Or at least they used to. I know they use that term for Chrysler "wedge" heads and for Ford heads.

[jerrysta]

Do Brodix or Dart make an LT1 head?

[RangerBob]

No

You can buy a SBC all aluminum block and heads from them though

Dart

[jerrysta]

I want to stay with an LT1 block because of the CPU and other bolt ons I have.

[jerrysta]

Can a non-reverse flow head be "made" into a reverse flow?

[94 formula]

Can a non-reverse flow head be "made" into a reverse flow?

Yes they can but unless you are looking for an extremely high flowing head its probably not worth the money since you will be paying so much for the heads\machine work.