Vinny P

[QUOTE=shawn]The cam is a custom grind from the engine builder. Lobe seperation is .110 on the intake side and .119 on the exhaust.



These numbers can't be possible. Check the #'s and post the correct ones. Maybe it will tell a better story of what the problem is.

articfriends

Sounds like you gave up bottom end and lower midrange for a little more top end. I also agree with the others that as a band aid approach you could advance the cam 4 dgrees more to try to recoup your bottom end with out spending much more money. Who ported your heads,Iv'e seen heads (even done it myself when i was younger)that were ported for big top end flow #'s that hurt the bottom end,especially with a little too much cam and too big of a carb(a common mistake someone that is used to building drag motors more than marine motors would make). cyl pressure is a good indicator of cam sizing also(old school thinking but usually still true) . I had a guy bring me a street/strip car that had a 10.25 compression ratio that was over cammed,he should have had 190-210 psi cranking compresion(from past experiences),it would barely idle and had a soggy midrange,i checked the cranking compression and it was only 155-160 psi,we advanced the cam 4 dgrees (still a band aid approach but cheap)and cranking compresion increased 20 lbs to around 180 psi,motor idled considerably better and gained throttle response and midrange. if you can,check your cranking compression #'s and post them,and If you do advance your cams could you post your before and after cranking compression or pm me with it,Smitty

CMS Racing

shawn call me at 410 335 2226 CMS RACING ENGINES and we can help you get it stright . I'm in your back yard . my shop is in middle river md

cobra marty

Peak TQ of 562 is about the same as the stock engine. That is why it is no faster. Build for TQ as it is what moves the boat.

robyw1

Your compression ratio is WAY TOO LOW for that cam. Add on a single plane intake and you are loading it up trying to get on plane. (explains your black plugs) I don't know who built this engine but they should have known this would have been an issue. I mean for crying out loud that engine's power curve is dropping off at 5700 RPM. It should pull strong up to at least 6700. I bet is sounds good but you either need to go 11:1 CR or run it on NOS. NOS loves those long duration cams I don't think advancing 4-degrees on the cam is going to help here.

Roby

robyw1

90%????

C'mon this isn't a formula 1 engine. I'd say low 80s at the very best.

Roby

TomR

I was trying to be optimistic, but your probably right!

robyw1

I'd love to have one though. Be a big step from my 45% 454EFI

Roby