budscom

Hi, I an new to this site but it looks like somebody will be able to help me out! I have a 98 regal 322 with 600 cfm carbs 454 DP's I have done all the basic tune up stuff like plugs, filters, wires, cap & rotors, checked fuel pressure etc. but I can only get 3900 & 4200 at full trim out of my engines . They have around 700 hours on them and I was going to pull the heads and have them rebuilt, check the cyls bores and if they check out I was thinking of putting in a more aggressive cam and larger carb if thats what it will take to get the engines to turn 4500- 5000 rpm. Anyone done this mod and have any advice or cam suggestions on this upgrade? Any input will be greatly appreciated.

HiPerf2000

iTrader: (2)

700 hours is alot. do a leak down test to see whats going on before you start tearing stuff apart.

budscom

I did plan on doing a leak down test and compression again, already bougth the leak down gauge set and compessor tank to do just that. The main thing I'm looking for is the right combination of parts. I don't know much about marine engine specs. The boat is an express crusier not a go fast, so I assume I should go for more torgue but not certian. What about running an alum intake in a fresh water boat is that going to cause any problems? My orginial thoughts were if the engines check out, to put a carb that can support 450 hp with a better intake and cam do a little bowl work on my rebuilt stock heads and let it go until I do a complete rebuild in a couple of years. I only put about 70 hrs a season on my boats sofar up here in the midwest. As far as alot of hours goes on my engines I put a whipple on my 454 Suburban with 90K miles on the engine and when I tore it down everything was in spec? I rebored it anyway but was supprised at how little wear there was. I have heard that 1000hrs is like 100K on a car? Is that a good rule of thumb.

SeaRay Jim

With nothing else changed, same props etc., have you been able to turn 4200-4600 RPM in the past? If not, if there is not anything obvious pointing to engine problems, have you investigated other things like props, hull condition etc.?

prosnd

I would check first and see what heads are on the engine. I have a 95 300 hp 454 Volvo with a 290 dp. in a Chaparall 2550SX. When I purchased the boat 2 yrs ago with 150hrs, it would turn to 4200 with a B4 prop set. giving me a speed in the low 40's The engine had the "peanut port" heads and cast intake with a Holley to quadrajet adaptor. I swapped out a pair of "Vortec" full size round port heads and the Holley dual plane intake, no other changes and my boat picked up over 10mph. In fact I had to go up 2 prop sizes to a B6 propset. The fuel econmy went way up too.
If you have the Peanut Ports get rid of them!
Another thing to remember, If you have a duo prop. the cam swap has to allow a LOW idle speed. the props are so efficient that a high idle from a lumpy cam will cause a problem around the docks. This is the reason I didn't change cams. I got so much power with the new heads and intake that I feel no need to get agressive with a cam. With my stock cam I can idle at 550 in gear and this still makes my min speed almost 4.5mph (gps).
If you want some more info on what I did feel free to e-mail me.
[email protected]
Cheers and good luck
Charlie

budscom

The hull is bottom painted and everything is in good shape. I can get 41-43 mph per the GPS at WOT with the engines running as described. I just want more! The one engine that only pulls 3900 did have nearly 10% variable compression between cyls. the other engine had all cyls at 140psi. That is why I suspect the heads, I'm pretty sure I have the peanut heads although I was told the engines are rated at 350 hp? No one knows much about Volvos here I even asked the dealer. Everything I drive is modified so why not my boat! Prosnd, it sounds like I what you did, is just what I want to accomplish. I have not heard of Vorted heads for a BBC? Is that a marine head? I will email you if you are willing to describe what you did etc. Thanks to everyone who offered advice / opinions etc. Keep em coming I'm always interested in effective mods for my toys!