Thread:

Info on a BBC cam selection

Ok guys im new to the boating scene and need some imput. I purchased a 1995 Velocity 260 with the motor out and apart. Im not really wanting it to be any faster than what the guy said it was (85mph), or thats what the guy said. But here is the run down, its a BBC 468, GM cast iron hi perf heads casting #14096188, in valve= 2.25, ex valve= 1.90. It also has a B&M 250 blower with a PFM super chiller intercooler, so i'll prob be running around 10lbs of boost on the setup also hopefully on 93 oct pump gas and with a 28 pitch prop. So here is my main issue, what kind of roller cam should i run or who should i call to order my cam? Other than that feel free to let me know ideas on my combo or if my goals are even realistic with what i have.

Thanks
Bolt

Thanks i'll have to give him a buzz and check him out..

Don't forget CSTRAUB here on the boards. He has made, or designed a lot of cams for a lot of people around here. It seems they have been very happy. Look him up.

What exhaust system? All the parts involved in the exhaust and where and how the water enters them. If this is not a max effort deal, a shelf grind will work well also. BTW compression ratio target would be good to know.

Originally Posted by MACHINEHEAD1

What exhaust system? All the parts involved in the exhaust and where and how the water enters them. If this is not a max effort deal, a shelf grind will work well also. BTW compression ratio target would be good to know.

Dont know who the manifolds are made by yet, But they look real pretty and are polished stainless. lol Also on the compression ratio, i havent got the parts checked out yet to know the cc's in the dish pistons or combustion chambers. But from what ive seen and know on the turbo motors ive built, I'm expecting it to be around 9:1.

Ok the best i can figure this evening the compression is right at 8:1. Thats if the heads havent been decked to much which i'll find out thursday.

Just to throw this out there. Did a 468, Merc 525 SC copy. Had the Crane 525SC roller cam 177 blower and a dominator with 6-7psi. Made 617hp and made a 24 Hallett (similar boat) do 83 @ 5100rpm with a 28" bravo with fuel and folks on board. I think the customer got 85mph out of it a couple times. Your deal at 10psi and the bigger blower will get you there. I think the Crane was 228/236 on a 114lda. Boat Idled awsome and shifted pretty good at 800rpm. Had Eddie Marine exhaust and dry to the tip. No chiller

Originally Posted by MACHINEHEAD1

Just to throw this out there. Did a 468, Merc 525 SC copy. Had the Crane 525SC roller cam 177 blower and a dominator with 6-7psi. Made 617hp and made a 24 Hallett (similar boat) do 83 @ 5100rpm with a 28" bravo with fuel and folks on board. I think the customer got 85mph out of it a couple times. Your deal at 10psi and the bigger blower will get you there. I think the Crane was 228/236 on a 114lda. Boat Idled awsome and shifted pretty good at 800rpm. Had Eddie Marine exhaust and dry to the tip. No chiller

Thanks for the info. My engine guy gave it look today. With the chambers on the head and the dish pistons she's a little under 8:1 on the compression. Now to flow the heads so i can order the cam.

Dont bother flowing the heads. Everybody knows what they flow. Im sure someone can post flow charts
with multiple stages of porting or just a clean up. Spend the money on a good oil system or other stuff.