bcarpman

Just thought I'd post the final results of my 7.4 buildup. I appreciate all the help everyone gave me. The scope of the project changed several times and I ended up not stroking the motor, and in fact, used the stock crank and Hyperutectic pistons since the bearings and bores looked so good even after over 1000 hrs (figured that meant I had a pretty straight and well balanced crank from the factory).

However I ended up doing all the work I wanted to avoid doing by keeping the engine mild (still reworked the cooling and oiling system, new carb, time on the dyno, etc.). If I had it to do over, I would have spent the extra $2k, but oh well.

I haven't added it all up but I think I'm around $4,000 total not including my labor (which I enjoyed), but including everything else, like dyno time, and pulling the motor from the boat.

Dyno numbers (Tyler Crocket's Dyno)
460Hp at 5200rpm
500ftlbs at 3800rpm
Over 450ftlbs from 3000rpm-5300rpm

We used a set of short tube headers so that we could run full instrumentation, so we figure I'll lose about 15-20hp with the 496ho exhaust without the turbulators which is what I'll be running.

I spent a lot of time calibrating in the part throttle range. With the high swirl L-29 heads the engine runs beautifully at stoic or leaner until you get to an rpm and torque that should put the boat around 50mph, so cruise fuel economy should be decent.

We had no mechanical hiccups, and with close to 6 hours of high load run time on the dyno, I expect this engine to be pretty bullet proof. Oil temps never went above 180deg even after extended high load runs (I need to rework the oil thermostat to allow higher oil temps)

Parts I ended up running:
-Stock 454 bottom end (rebuilt)
-L-29 Oval heads w/ severe duty stainless valves and good springs, pocket ported by Jason Hayward
-RM 202 Competition products Roller Hydraulic Cam .550 lift, 229/[email protected], 114 lsa
-Morel roller lifters
-Edelbrock Air Gap dual plane manifold
-Gary Williams 4150 800cfm Carb (The Weber I so carefully reworked flowed great, but didn't deliver enough fuel over 450hp. Still not sure why, but I'm guessing when I ported all the casting flash off, I also lowered the vacuum signal to the secondaries)
-496ho short runner aluminum exhust manifolds with turbulators removed.

I did all the powder coating myself, and if you're wondering about the weird colors (red and purple) they match the colors that run throughout the boat.

Again, thanks for everyones help!!!

cuda

Looks great. What year was the original engine?

bcarpman

It was a '93

ericaull

Looks real good .....install it and let us knowhow she runs!!

bcarpman

Yes, that will be interesting (literaly). I have a lot of experience taking automotive engines from the dyno to the street, and am pretty confident in how that translates. We'll see how well it goes from the dyno to the water.

I'm putting one wide range O2 in, and have bought a selection of Holley jets just in case. I'll hopefully drop it in way before the warm weather hits so I won't miss any real boating if it needs some tuning.

1BIGJIM

iTrader: (1)

Is this a custom cam?

-RM 202 Competition products Roller Hydraulic Cam .550 lift, 229/[email protected], 114 lsa

bcarpman

Not custom just for me. It's a regrind off a stock blank. A marine engine builder that does work for a friend (isn't on OSO) recommended it to me as a really good mild improvement over a stock 496ho cam. It had the sort of specs I was looking for, and I think it turned out to be a really good choice.

Competition Products number is 1-800-233-0199

dykstra

iTrader: (1)

congrats

phughes69

[QUOTE=bcarpman;1995387]
-L-29 Oval heads w/ severe duty stainless valves and good springs, pocket ported by Jason Hayward
QUOTE]

Bcarpman, doesn't Jason work at Katech?

Payton

Looks good! All those colors should give you a few more HP.
Hope it runs as good in the boat.