I spoke to Stainless Marine today and it sounds like their BBC exhaust manifold offering is the same general design as GILS with no seperated runners. They said the height of the risers and where you inject the water into the pipes (or not at all) makes all the difference with the reversion issues (makes sense). I have not had a chance to talk to KE about their isolated runner manifold yet. From the pics it looks to be very upswept like headers so water would have a harder time pulling back in. This whole manifold thing is becomming a major PIA though...

If you havn't bought pistons rods etc yet, I would definately stroke it to 540+ !!!! It would be cheaper than exhaust manifolds and Im sure you will get your 650hp mark fully dressed maybe with the same exhaust and some afrs, rm builder cam etc to suit !!!! Cost of the build now to do it would be price of crank and block clearancing soon you are replacing everything else already......plus its alot easier & cheaper later to add an exhaust than to stroke it later would be out of the question !!!!! My 2cents on exhaust KE heard very good inc reliabilty or even Imco powerflow PLUS series alot cheaper and also excellent reliability.

I run 509's 5800rpm, 580hp with imco powerflow exhaust (similar to your gils NOT the Imco PLUS series) RM Builder cam, afrs, and holley 800's. Im sure I could pick up maybe 20-30hp with 850's and decent exhaust but getting extra 70hp to reach your 650 figure would be a real push !!!!! I wanted to stroke mine but im sure my speedmaster 2's wouldnt of agreed !!!!

Call RM builder as he has done alot of Cams for Similar 502,540's etc with AFRs. I would trust his advice 100% and definately use his Cam choice which ever setup you decide on.

Thanks, I'm debating blowers vs stroking right now. Considering durability and the fact that we've overheated in the past, we want to stick with iron heads.