For some quick background the motor I'd like to turbo is a 557 bbc that is 8.36 to 1. I picked up what I think is a deal on just banks manifolds and risers. My risers for some reason ARE set up for a blow off valve. I have alot of questions but the biggest one is will these work in a blow through application? I can't see why they wouldn't, but every banks set up I've ever seen was draw through. I'd be tempted just to change my mind and go draw through but I'm told that because the banks deals were designed around a 454 cid motor, when put on a larger motor they tend to have fuel dist. issues. I really like the idea of the manifolds being cooled as opposed to a non jacked set of pipes. I don't think I'm lookin for huge boost here maybe 5 to 10 psi, I've got a lot of different feedback on how much boost will be safe at 8.36 to 1 on pump gas. I was going to stick a pic or 2 up but I don't see a user cp to upload pic to. TIA Kreg

 

I see no reason why it can't be setup for blowthrough. I don't really like drawthrough setups since they really don't like much restriction, whereas blowthrough is MUCH less picky on that issue.....and most around here seem to agree that blowthrough is better.

 

Thanks, I'm still open for turbo sugestions, I'm a little worried about back pressure from the logs being too restrictive, I'm not sure if bigger turbos will have more or less back pressure, I'm still trying to wrap my head around the whole turbo deal. Btw the manifolds are set up for t4 turbos. Does a couple of 72's sound about right?

 

I would call a turbo shop like www.forcedinductions.com oh and ls1 f bodies have made north of 1500hp on stock truck manifolds.

 

Here's a few pics I got off this site comparing turbo sizes.
The big one is a S480. Two of those or S475's would be good for your engine. I just bought two new S475's for my 540 ci. engine.
The small ones are close to if not larger than what comes on a Gale Banks setup.

 

Thanks Unchained(Mark) I keep hearing 475's ,I was confused because those are t6. To clarify I just called Bullseye, and they told me t4's (475's)were doable but would be like 1k ea So then I asked what the price of the biggest t4(300 series) was and it was more$ than that At this point I may look to fab up my own headers with a t6, I dunno ? The price of h.p. just went up for me.

 

I build stainless headers for others. They would be dry pipes and with a T6 flange.
It's a big fabricating challenge and the material costs are high.
Call me at 616 813 7237

 

Thanks alot for the offer Mark, I may take you up on it soon. Besides the fact I don't have $ for headers right now, the heat issue concerns me. I'm leaning/hoping I can have you or someone make a y pipe to merge the two t4's into a single t6. The biggest thing that concerns me about that is the holes in the risers(where the t4's would go) are only 2" x 2.25". It just seems like it would be real restrictive on a 557 inch engine. Any input on this from you or anyonewould be appreciated.(even if it's not what I want to hear)

 

Man , with that big of an engine you sure do need to step up to the t6 flanges and twins. I'm afraid that if you dont that your engine will be all done by about 4500rpms or so.
If you do decide to try the smaller setup then at least put a huge set of waste gates on it so they will open up and vent the backpressure, this will help some but its a bandaid, but should be OK for 10-12 psi .
I'm presently running a set of the banks logs also but Mark made me a set of stainless headers with the t6 flanges that I will be going to in the near future, should be a large increase in hp.

 

Nuff said, thanks.