S10 - HT3.4 - Head Upgrades

[GEARS]

Hey guys I have been looking at this site for a while and decided to join in on the 60* family. This is my very first post.

This past summer my 16 year old son and I did a HT3.4 swap to our 1986 2.8 S10 2WD with a T5. We added a 400 cfm Holly TBI, ported intake, MSD ignition, Edelbrock TES headers, Flowmaster 50, 8.5 plug wires, and rapidfire plugs.

I have been learing lots of information about these 60* motors. I know the Gen I iron heads on my 3.4 have a horrible flow, something like 135 cfm per cylinder!! I know how to swap to 3400 Gen III aluminum heads which are known to flow much better... But I really dont want to lose my TBI setup, as I know there are no aftermarket TBI manifolds that fit the 3400 heads. So I want to stay with my iron head setup to keep my TBI as in the future I may want to install a Fageol Supercharger.

My question is, is what cfm does the 3400 heads flow?? This way I know how much work I need to do to my iron heads to flow just as well as the 3400 heads. And yes I am willing to pay the money of port/polishing.

Any help is greatly appreciated. Thanks!

[1QUICKHATCH]

the 3400 heads flow over 200cfm on the intake and 135+ on the exhaust stock. If you have enough hood room I would use the 3400 heads and modify a 3400 lower to allow use of the blower, or just start with a different blower.

[Superdave]

Don't just look at peak CFM, averaging the numbers will show you a bigger picture. That being said, even if you could get iron heads to flow as much as stock 3400 heads you still wouldn't have the advantage of the fastburn chambers.


I bet if you bolted on a 3500 top end you'd forget about that S/C for a long time. Maybe long enough that there will be a better solution for bolting a blower to 3x00 heads.

[geoffinbc]

Now your into new pistons, new manifold/s, new exhaust, new or modified accessory drive, new EFI system. I am not saying don't do it but just be aware it will cost money and most of the parts you have invested in already wont work. It wont be a weekend job either. In the future I will be doing a similar job on my S-10.