BOBALOO

Let me start off by saying that this forum is the BEST one on the net. I've been reading for about 1 1/2 years and have learned alot from everyone without the useless BS those other forums have. Heres my setup, 96 Eliminator Eagle 25' 454 mag all stock. I have a 24 pitch Bravo 1 and turn it about 4850 rpm for a gps'd 66.4 mph w/a full tank 3 people big stereo ,batteries,tools, 3 coolers and all the stuff that normally I dont need for a couple days on the lake. My question is does anyone have any REAL WORLD IMPROVEMENT with just changing the cam ,valvetrain, carb,ignition, and flame arrester.I already have everything but the cam from old boats and for a few mph would probably do it. From what I've read the crane 241 is the one for me. The last boat(jet) had a comp cam extreme with approx the same specs but was supposedly faster opening the valves. You know what they say about opinions,everyones got them so here goes. Thanks. btw I already put my 4 hole spacer and 800 cfm Holley on with no improvement except starting ease.

Cord

I would keep the basic motor stock, those mags are really put together pretty well. You will see an improvement with a header exhaust. Look into Lightning, they're a little more affordable. You can also turn the mag a little harder than what you are. 5200 is OK. How many hours do you have on it? At a little over 500 hours my motor started to lose power, so that would be something to consider. A B&M 174 or even (better) the 250 would really wake up your motor. You'll be over 500hp easily. You could also look into a 2" shortened lower unit. With a prop change and the lower, I saw a 5mph increase.

Real word improvements? The items I liste above are the most feasible/effective changes you can make. There is very little power to be found in the valvetrain, carb, ignition, and flame arrester. The money you spend on those items would buy you the exhaust and you'll be going faster with the exhaust. The biggest gain will be with the supercharger. The next biggest will be with the shortie.

BOBALOO

I've read everything and nobody wants to admit that they only got 1 or 2 mph.They only reply with it runs great.

Whiteknuckle

Welcome Aboard,
You got not improvement with the 800 CFM Holley over what, a q-jet, or what? Normally the 4 hole spacers may give you a little better low end and the open spacers a little better top end. I said may.

BOBALOO

Thanks cord . the insurance for a blower might kill me and I already have everything except the cam from old projects. If I found a cheap 177 I might consider it. I also like to boat in shallow 5' sometimes water so a labbed prop is'nt smart. I am not really asking about an engine combo as much as what others expected and recieved.

BOBALOO

The boat has 250 hours and I switched the carter to the holley and added the four hole to get some more bottom end because of all the extra weight I put in it .No regrets. It also has a step hull and rides very high in the water with little trim so I dont think a hp increase should screw the ride up.

Gary Anderson

Look at the specs for the 400 or 420hp cyclone motors. They're pretty much the same as your 454 with a different cam, intake, carb, and exhaust. And realistically you probably wont get much more than a couple mph.
BTW, no need to change ignition, the T bolts are great.
If you want a significant increase in speed and performance, bolt on a blower, carb, and V6 ignition.
My $0.02
Gary

bobl

BOBALOO, I had that exact engine that I modified. I rebuilt the engine and zero decked the block. I went with a set of ported 310cc Merlin heads, Crane 731 hydraulic roller cam, Edelbrock Air Gap intake/800 Holley, and stainless marine exhaust. My final compression ratio came out to 9.4:1 so it needed 91 octane. I went from 59 MPH to 70 on GPS in a V bottom boat. I think if you ported and put larger valves in your GM heads they would work almost as well. If you stay with a flat tappet cam it will cost you about 25 HP from what I had. That engine is still running great with about 400 hrs on it.

Bob

BOBALOO

What I have is the t-bolt V with the knock sensor. What is the rev limiter set to and the total advance built in. 806745-4 it also has another module that has AZ/CA 888749 6M what does what and should I keep it? I've also read that the initial advance is'nt adjustable on this setup,why not?

Strip Poker 388

I dont know what the diffrance in years would be but

I pretty much did the same thing .1990 Motor had 350 hours on it. Had a valve guide go out on #8 exhaust so it smoked when you cranked it.Went with the merlin heads and ported them ,cc matched the chambers. 1.7 roller rockers.Stock lift was 510. i was ok on the coil bind,they had decent springs. Stelling headers,water cross over ,no water pump,holley 830 cfm anuler,1/2 phenolic 4 hole spacer,the stock alum dual plane intake ported,Gaffrig 8x5 flame,ngk plugs r5674-7,stock thunder bolt 4 ,It did not like the timing base at 10 so i left it at 8.Wish I had the MSD at the time.this was a 28 Scarab heavy hull. It picked up 300-400 rpm top Rpm was 5400(from the rpm on tear downs never showed any probs bear-rings were good) and about 4-5 mph on a good day i never changed props.Just buzed the motor. at 69mph it porpoised ,so it might have done better.This is just the high lite on the parts.

Next time around I went thru the hole thing and went crazy .big roller cam and 8/71 blower ,inner cooler 2 barry grant 920cfm. Same stock bottom end with blower pistons ,with all the usual stuff done to the bottom end. at 1 to 1 made 8-9 pounds of boost at 7250 762 hp.this was with a stock 365 mag bottom end.


I would prob port the stock heads casting # 188 or 292 The flow pretty good, Need to weigh the cost of porting over the merlin heads. stay with the rectangle ports!.every body usually goes with the single plane intake, Dart too expensive ,i would go with the Eldebrock super victor,

Good luck
Rob


my 365 mag came with a 800cfm quad jet .Probably the reason you didnt pick any ,no diff in cfm over stock. You got to remember the motors where real close to the old 1970 Ls -6 motors that came on the Chevelles claimed hp 550.1969 and down i think had the quadrajets.Compression and cam was the diff.