Jeff Pierpont

I needed to get around 450 hp out of a stock 1999 350 mag mpi any suggestions , right now it's around 300 hp and i would like to keep it fuel injection. Jeff

Smitty

iTrader: (1)

To get that kind of increase you will need to supercharge it. I recommend a Whipplecharger.

Dennis Moore

You will need an aftermarket fuel injection system, stroker crankshaft (383), solid roller camshaft, higher compression (92 octane) and individual tube exhaust headers. The engine will need to run at least 5800 rpm.
Sincerely
Dennis Moore

Jeff Pierpont

I don't what to overhaul the entire engine ,just maybe change the cam or heads to add in the performance of this engine.I believe the stock cam is the same for all the small blocks that seems strange knowing different cams can change the performance of an engine.Jeff

Dave F

cam profiles make all the difference in the world.

However, to get 450hp from a 350, (and stay nat. asp.) the only way is to use race fuel and have really high compression. Not desireable in my opinion. Or do what Dennis suggests, bump up the cid and use premium fuel. It's just a little more work invoved but the cost is comparitive to adding a blower. (depending on prices in your area of course)

But since you don't want to overhaul the bottom end, a blower, cam and heads will be the way to do it. Even then you're talkin' between 6-8#.

GM had a ZZ430 limited production motor out in like 1999, I think. I'd have to look it up for you when I get home, cause I cant remeber the specs. I do remember it had the "fast burn" aluminum heads and the "hot cam".

The fact remains that there is NO cheap/easy way to get that hp from a 350.

my .02
DAVE

Jeff Pierpont

Dave what is your email address . Thanks Jeff

Griff

To make it at all driveable and have a decent idle an SC is about the only way.

I had a 350 in a street rod, built with good internals that I ran a B&M 174 on and that made right around 440hp at 5800rpms. I was running at least 8# of boost. It still needed to idle at 1000rpms in nuetral to keep it from dying when put in gear.

Dave M

Will a big block fit in your boat? A stock 502 MPI is close to that amount of HP, runs on 87 octane, and relaible. You might find a used one for what you will spend souping up your 350.

Jeff Pierpont

A big block or a blower will not fit under the engine hatch and i would hate to have to cut , seeing mercruiser uses the same cams for all there small blocks,do you think changing to a bigger cam and better set of heads will be worth the money,will this mod. make make improvement. Jeff

traviss

Hmm first thing.. throw away that MPI It will take a good amount of money to get to 450 hp with just some top end work. You will have to get into the bottom end and do some work if you want some good hp. For a idea of what it takes for hp for small blocks, I have a 383 that has AFR heads, roller cam, single plane intake, 750 holley, EMI exhaust and a 10.9:1 comp ratio on 110 octane. It probably only makes around 500 hp at 5500 rpm. This setup idles at 850 rpm and never loads up while in no wake zones.

With that new of a motor, your motor should have the chevy vortec cast iron heads, which are a very good flowing head. You would not gain much changing to aftermarket heads unless you spent a good chunk of money. and I beleive your ignition has a rev limiter too..

just my 2 cents..

Travis