454 rebuild - ugrade help
 

New to this forum. I came here because you guys know engines. I currently own a 37 foot Sportfish bridge boat with a pair of 1988 Crusader 454's with 1700 tired hours. I'm looking to rebulid but also want some additional torque and HP. I would like to be able to run between 3500 - 3600 rpms at cruise.

At first I thought 8.1's would be the answer but they're not made anymore and bit more than I wanted to spend.

What I'm looking for is if anyone knows a reputable builder I can send my engines to or do a swap to acheive more torque and HP. I'm located in Wisconsin so the closer the better.

Also, is it realistic to expect my engines to perform any better on 89 octane? I would also like to convert them to TB injection. Unfortunately the heads are the small peanut ports.

looking for some help and direction or any other suggestions. My budget for this project is 10K or under.

Thanks

You'll need at minimum 35k more..

Fixx
 

what part of wi?? do you have reverse rotation engines??
if do then you mat be limited to parts involved..

i have been using opel engineering for years,they have all up to date equipment including cnc machineing..
they are located in streamwood il..

http://www.opelengineering.com/

ask for ted..

Yes - I have one reverse engine.

Haxbyspeed - WOW! 35k or more! to rebuild 2 454's??? When the 8.1's were avaiable I could have bought 3 new turnkey engines for that price. I'm just looking to get them rebuilt with a little bit more umph.

If I were you I would re-power with 502 MPIs, but I don't know if you'll be able to find one Rev. Rot.???

You don't have to buy the junk 8.1's to get to 496 cubic inches. You can stroke your current 454's and make good Hp and torque in so doing. That said, you're going to have $2k each into the kits, + machine work, + assembly, + the R&R, + new heads (you're going to want large ovals), + new cams (and limited options due to the Rev. Rot.), + new intakes, + new carbs, and you may have to replace your exh. manifolds.

It's definitely not a cheap endevour. What is your current cruise at? You may be able to do a simple rebuild and add large ovals and intakes and pick up 30-40 hp, but that may not be enough to get you to where you want to go...

First do some research on the topic. You are not Limited because it’s a reverse rotation engine.

Depending on what needs to be replaced after you tear it down, you should be able to rebuild what you have cheaper than 10k. You will need pistons, you can resize your existing rods using ARP bolts. If you can use your crankshaft have it turned. Heads will probably need a lot of work.
You can get a custom made cam just like a normal rotation cam. They don’t uses gear drives, timing chains. Seals are different because of the rotation.

Or you can buy brand new GM MARINE crate engines. I looked at 1800runsnew website. They have 454 GEN 6 with roller cams $4,749 and $5,549 for opposite rotation.
Or for a little more coin move up to 502 GEN 6 engines. If you called them I bet there prices are a little more than they have posted.

Do some research and good luck.

Ok, been down this road...depending on the transmission in your boat..if they are 72c BW you need to stick with what you have...find a good engine/machine shop...keep your gen IV's the way they reverse the gen IV's is not a good set-up I know have one now...I would say a good rebuild using forged pistons, think about just buying new larger oval port heads, several companies make them..just make sure they use the good valves for marine use, use a std edelbrock performer intake, I even use the edel carbs as well...the TBI setups might work but are going to be expensive for what you gain...if your cams are ok...use them with new lifters, if the cranks don't look good...then a stroker kit making them 482-489's will work well...that should keep you close to your $$ if you don't have to go the stroker crank route..good luck..Rob

you can do that on your budget if you spend your money wisely. i put together a approx 450hp 454 that started off a 330hp block, i have less then 4k in it and i started from scratch, i had nothing more then the accessories off the old gen 4 motor on a pallet. if you are not going nuts, rebuild the short blocks, forged is better but if you are not going nuts i think hyperutectic pistons are fine. find some of the newer vortec large oval heads, you can get ehm cheap. do a good cam, i used a crane 731 i got used for 200. find exhaust, that was the tough one for me but i have the hp500 gils that i have less then 500 into but that was a lucky score and i bought the risers seperate form the manifolds. edelbrock dual plane intake, holley 750, k&n flame arrestor and you can keep the mechanical fuel pump on yours. if you shop right and dont mid good used parts 10k can work... maybe a little more if you pay someone to assemble it. just my opinion and what i did.... i wasnt going after a rocket ship when i built mine and i am on a tight budget.

My vote would be rebuild them back to stock. you got 1700 hours out of them. Considering they are crusaders, i am gona guess they are in a cruiser style boat.

All the above mods are useless unless you go to a good exhaust system in my opinion.

If you are serious about more HP and torque, then you will need

Better heads.
Better exhaust.
Bigger cam.
Better intake.
Better carb.

You can make 500HP out of a 454. But you are gonna have to spin it to 5500rpm, and you really arent going to gain much power in the 3500RPM range. You'd probably be better off finding some 502 blocks to build off of. Some good oval port heads, a mild cam without too much duration. Something along the lines of the 502HT engine from GM perf. They designed it for truck towing applications. Lots of low end and midrange. Thats what you need.