prerunner404

Any one have good bolt on upgrades or a package of upgrades from some one? right now motor is 454 and carbed think its a 98 or so. anyones thoughts?

endeavour32

iTrader: (4)

Is it a base 330 454 or is it a Mag?

Swamplizard

I've got the same question - pair of 454 merc closed cooled 330s and I could use another 100 hp per to push my pig of a vessel. Other sites say it is a "nogo" without a complete tear down, forged everything, head changes, compression changes, carb changes etc....and for the hassle and money buy some 502s and start over (like we all have $20k lying around). Be very interested to see what this site comes up with.

I'll be lurking!

endeavour32

iTrader: (4)

You're going to get the same answer! The 330 is no good other than stock form. The crank and rods are not strong enough and the pistons are really low compression. In order to build more power you need more RPM's and the real limit to the cast crank is 5000 rpms. So can you increase the power, yes! Can you increase it to 430, NO. Not if you want it to live long.. If you have to do it, you could put better heads and a slightly better cam in it, but I really don't think it would be worth all the trouble. FYI, it's not going to cost $20,000 for a pair of 502's! A lot of guys have had good luck running create 454 HO's and ZZ 502's! Or look for a nice pair of take-outs. They pop up on here. There is a pair of rebuilt 425's in the classifieds for $9,000 ready to go. Sell your 330's for $5000 and your half way there!

Swamplizard

I was hoping that adding a small blower like a 177 would bump the HP/torque enough for my needs and still live if kept under 4800 rps and babied but even that aparently is not the case....too much heat and too much load in my application so it would die.

wjb21ndtown

You could do well for yourself to get a set of large oval heads (Merlins, GM casting 049 or 781s, or Edelbrock), and a matching oval intake. Right now your heads are the most restrictive part on your motor, after you do that upgrade it will be your cams. You can reasonably make 400 or so HP with your stock lower end, but you should at least buy 454 Mags if you want to make real power.

I wouldn't SC a 330hp cast motor, but some people have and got it to work fairly well.

Do a search for 330 roids motors and you'll get tons of advice.

prerunner404

i dont think its a mag it just shows 7.4l/v8 bravo on the carb cover so i think its a 330 hp version is this true? what would swapping it over to forged internals cost the motor has almost 400 hrs anyways so im thinking of rebuilding it soon

endeavour32

iTrader: (4)

Just stoke it to a 496. If your buying new crank, rods and pistons its very close to the same cost. If your block is a two bolt just stud it. It will be plenty strong. I'm not sure when Merc started using the newer 454 heads. If you have the newer version you may be able to reuse them.

Griff

Just leave it alone. You would need to spend spend 5k to see any real HP or speed increases.

pantera232

I did my 454 with cam, intake, 781 heads, domed forged pistons. , i had to extend tail pipes bc reversion ,new prop on boat gained approx 10mph i already had sm exhaust manifolds. it did cost approx 2-3 k