crowntow

I have an 28 foot Volocity with 502 MPI. I am going to be doing heads cam and exhaust swap and I am also ditching the fuel injection and going with a carb. I know many of you on this forum have done 502s. What is a proven package that some of you have used and what MPH and horsepower have you gained? Also is there a place that you recommend buying the parts from? Any input would be very helpful. I am going to do this swap within the next few weeks.

stevesxm

you are making a mistake by switching from the injection.

KAAMA

Contact RMBuilder/Bob Madara of Marine Kinetics in N.Y. 585-654-8583. Bob has done many cam profiles for many hi-perf offshore boaters here. He will take all of your engine's components (CID, heads, exhaust, ect) and match up a cam profile for your application and what you're looking to do with your boat. Bob can also set you up with heads.

He's at least worth a phone call.

Chris Sunkin

PM arcticfriends (smitty) or look up his posts. He's done a bunch of work with heads. Short version- his best result was with the AFR 315CNC head. Exhaust- probably the best for the buck is the Stainless marine Gen III. The Eickert is maybe a hair better but much more expensive. Plus, Stainless will do a better job working with you in getting the exact fitment on your tails. Tubular exhaust looks racer-cool but it's very expensive and more prone to failures. and you probably won't see but a couple additional HP out of it. On cam, PM Bob Madara- RMBUILDER. he can custom-grind to your exact application for the same as an off-the-shelf Crane cam. He's got the new Morel hydraulic roller lifter that he says is phenomenal. Bob can also help you with a deal on heads too.

Chris Sunkin

You type faster.

SB

I like to point out that that is your opinion.

If he or his mechanic is better at tuning carb's, than the carbs will be better.

And that is my strong opinion.

Chris Sunkin

Your reasoning is less than valid. How about we toss a third variable into your logic stew- take it to someone that knows what they're doing. Given that key element, injection is more reliable and runs cleaner/smoother than carburetion.

SB

I must admit my response above looks like I was going against the person I quoted very strongly. I should have put an emotican in it or worded it differently. My bad.

I do feel strongly that if the owner is very comfortable around carbs or his go to guy/mechanic is but not as comfortable around that exact FI system,than carb it is.

We (saying we as in general - everyone) can argue carb vs fuel injection all day. Both have there pro's and negatives. One or the other is not 'the right' choice over the other until we put the human that will be tuning it.

That's all. I deal with FI (different system) all day and I really like my Holley's.

I know and work with some people that have never touched a carb but are dead on with programming EFI. Therefore, I would not tell them to go carbed. Wouldn't make sense.

SB

If keeping the EFI, please note that the 502MPI intake system will really step on the airflow and thus power producing capabilities of good cylinder heads and camshafts.

If really wanting to step up the power and wanting to keep the FI I would strongly suggest a different FI intake manifold.

For carbs, Dean Nickerson, Prosystems, Willy's, and others can make a carburetor razor like. Many big Dom's out there idling like a 600 vac sec.

Speaking of RMBuilder, he has many engines out there he's spec'd the cam, heads, carb, and more. He was also part of Smitty's (arcticfriends)large project using the 502MPI intake. A lot of focus + effort was put on that intake.

He is a great source and very intelligent with what parts work with what. He is 'tuned' in. Very good resource for all us performance boat enthusiasts.

KAAMA

No....I just didn't type as many words as you.