Hang Time 27

In the mid 90's Jim Benny of Balt MD area rebuilt my cam wiped 330hp type 454 into 470-480hp for me for cheap. Used stock cast two bolt crank, flat tappet hyd. cam, took stock oval port heads and enlarged the valves, better springs, used set of roller rockers, stock shot peened GM rods and a slightly used set of forged pistons. Used "stainless marine" exhaust manifolds - all you need in that power range. This engine went almost 500 hours before a fire took it.
Took my little 20 ft monza from low 60's to 76MPH with a volvo drive and 28" pitch prop, and then it took my 24 excalibur to 80mph. No expensive parts needed in that power range.

1. Rebuilding my Longblock = $3,500
2. exhaust= $1,500
3. terrorizing passengers with the wind distorting my face for 4+ years = priceless

scarabfun

mine will be dynoed soon so i'm realy looking forward to see my number's. we're estamating on my number's now so i'm hoping for 500+hp with 550ftlbs tq. also my merlin head's are iron and i know alum. would make more power.

HaxbySpeed

Not always, iron or aluminum doesn't really matter. Other then heat shedding and weight savings aluminum doesnt give you a performance advantage over similair flowing iron heads.

niceguy

Hell Yeah HangTime27.... thats exactly what I'm talking about.

We should start another thread titled... "what engine combos and power made ". LOL

Good example for just wise parts selection and careful assembly that will net big gains.

Haxby.... sounds great man. Now throw a great port job on them things and I'd be a 30-40hp increase... and that would put the 454 (461 @ .030) at 540-550hp with good reliabilty.

Thanks guys.... this is fun.

niceguy

The only way the aluminum would give a power increase is by allowing a little more compression without the detonation that would occur with iron heads.

HaxbySpeed

Yup, and bump up the compression. The 510hp package was only 9:1.. I'll be dynoing a freshened up 525SC with lightly worked edel. heads and a smaller cam next week. Can't wait to see if we can make 600hp for cheap..

HaxbySpeed

"heat shedding"
still a somewhat disputed topic

gaiter

I am not sure what I want to spend, I am just trying to figure out if it is worth working the 454 or getting my hands on a 502. I understand engines and how they work, done a fair amount of work on them as well, but mostly maintenance stuff - the deepest I have ever got is head gaskets. I am a snowmobiler too, so lots of work on two strokes. Modifying engines for more power is new to me though, outside of strapping a set of headers on an old camaro.

I guess I am just looking for some ideas, and opinions on whether or not this 454 is worth working on. Again, reliability is very important to me, and I don't want to be reworking it every year. I would prefer to stay out of the bottom end of the motor. Almost every post here does include head replacement, is this because of the "peanut ports"? Would the motor really take a supercharger "as is"?

DMOORE

I agree with others. 500hp out of a 468 is not hard to do. And at 500hp you don't have to have a 4 bolt block, or forged crank. Just be sure to use top quality ARP fasteners. The key to the HP will be in the heads and cam. Try racejunk.com for some good, clean used ARF heads and talk to a cam builder for the right set up. Years ago I did just this in my Scarab. Went from 454 to 468's, had a very good machine shop do the machining, and I assymbled the motors myself. The KEY, is to have the proper clearances for a marine engine. There are plenty of experts on here that will share some info with ya for your project. BTW the whole project was not very expensive and the boat was completely transformed, without breaking the bank.


Darrell.

Ryan8886

Haxby,

Just curious.....what would a job like that cost. My peanut-port 454/330's have about 500 hours on them. Thinking maybe in a season or two of making some minor changes like that. So what would a ballpark cost be? And would the Bravo 1's stand up to it long-term? Another question....can you rebuild one motor at a time instead of both at once or does that mess with things? Man I'd LOVE someone to teach me how to rebuild a motor!