The 502 in my Velocity VR 1 is being bored to 540 and rebuilt. Horsepower will be north of 600. My original exhaust is CMI E tops. Problem is that they are the model that doesn't use tail pipes, just a rubber connector from the elbow to the through hull tips. Builder is recommending either CMI E tops with tails or IMCO Plowe Flow with SS riser. As I had some cylinder damage with the original (non-stock) 502 he wants the water introduced further back then my old CMI without tails. He is OK with either choice.

Besides the fact that the CMI is prettier and the IMCO are less expensive...What are the other pros and cons. I do wonder how changing spark plugs are with the IMCO. I am not as limber as I used to be.

Thanks for the help, deciding.

Padraig

Go with the CMI Elbow Tops. They look great and last forever!!!

I have the black (powder coated) Imco power flow plus manifolds ....Attached to 572 cu. in. tall boys ~ back in 2018 (2) sets of black manifolds & 30* risers
cost $5,199.98 from CP performance. I can get under them to change spark plugs easily.....

Thanks Skippy. Any idea of how the Power flow and power flow plus are different?

Padraig

Same here... mine have been on the 311 (TRS tails) for over a decade in salt water and not one issue. I pressure test with air and heat every other year... still going strong.

550 hp would be border line for the Power Flow manifolds ...above that, I would go Power Flow Plus reason being their ported to flow better for above 600 hp
Also, the tail pipe accessory is different than the "plus"....https://www.cpperformance.com/c-436-...ock-chevy.aspx check out the differences between them.

Might want to check into extending the one piece E tops you have. Have a good welder make them like the older CMI Unitops

I thought boosted engines did not usually have water intrusion from reversion. Griff's comment above, ^^^^ makes the best recommendation with probably the best cost too.You are likelt only looking at a few hundred vs several thousand $$.

Cmi look cool. We had issues with bad welds. Stainless marine ftw

With E-tops or full long tube?