engine swap

[johnbrennan]

Hi i would like to repower my 21ft aluminum cheiftain from a 3l to a small block V8 ...any ideas what size would give me the best bang for my buck..using same through hull or not
Thanks

 

[Bondo]

Re: engine swap

Hi i would like to repower my 21ft aluminum cheiftain from a 3l to a small block V8 ...any ideas what size would give me the best bang for my buck..using same through hull or not
Thanks

Ayuh,.... Welcome Aboard,.... The logical answer is a SBChevy...
Which 1 depends on what ya find, 'n for how much...

Ya do realize, ya gotta swap out the Whole driveline, from Pulleys to Prop, Right,..??

 

[johnbrennan]

Re: engine swap

Thank you for responding....my reasoning is to go from 140 hp up...by going to a v8 i will add 250lbs to the stern of the boat...will that effect my handling? also what size of engine sgould i look for and should i go short or long block

 

[ezmobee]

Re: engine swap

Your best bet would be to find someone selling a rotted out fiberglass boat with a complete driveline. Heck even a complete driveline with a cracked block + a new block would probably be cheaper than trying to piece it all together yourself.

 

[RogersJetboat454]

Re: engine swap

what size of engine sgould i look for and should i go short or long block

Not sure if your confusing size (as in external dimensions), with displacement (as in combined cylinder volume).

If it's external dimensions your worried about, ALL small block Chevys have the SAME external dimensions.
If you're asking about displacement, either a 305/5.0L or 350/5.7L will fit the bill. Depending on how the engine is equipped, your typical 5.0L engine will have an output of 200-220+ HP. A 5.7L will usually be around 260-280+ HP. It's your decision which one you want to go with.

Also, in regards to your question about short block VS long block. I'm not sure if you're confusing block size with how the block is equipped. The terms "short block" and "long block" don't have anything to do with the actual dimensional length of the block.

A "short block" engine is traditionally a cylinder block with crank, rods, pistons. May or may not include cam shaft, timing chain, and oil pan.
A "long block" engine is everything a short block engine is, plus cylinder heads, valve train parts. May or may not include oil pan, timing cover, valve covers, harmonic balancer, and an intake manifold.

If I were you, I'd heed the suggestions of the others, and find a complete matched engine/drive package with all the ancillary bits and pieces. It will make the process allot easier in the long run.

 

[cr2k]

Re: engine swap

As stated your outdrive will have the wrong gear ratio for a V-8 and need to be changed as well. From a 3.0 to a V-8 is way more then can be corrected with a prop change alone.

 

[johnbrennan]

Re: engine swap

Thanks guys...i bought a complete boat for 800$ that has a cracked hull...its has a 5 litre mercruiser with a 188 outdrive in excellent running order...now my next question is....are the shaft centerlines line up or is modification in order for it to fix and will the boat sit *** heavy in water

 

[Bondo]

Re: engine swap

Thanks guys...i bought a complete boat for 800$ that has a cracked hull...its has a 5 litre mercruiser with a 188 outdrive in excellent running order...now my next question is....are the shaft centerlines line up or is modification in order for it to fix and will the boat sit *** heavy in water

Ayuh,... The crankshaft center line don't change,....

'n, Yes, of course it's gonna sit low aft, yer addin' over 250 lbs to the transom...

 

[johnbrennan]

Re: engine swap

Awesome thanks a lot you guys...will repost more questions when i get the donore boat on the 14th of march....btw can i post pics for youse to see

 

[81 Checkmate]

Re: engine swap

Yes post alota Pic's......Is this 5 - L.... a FORD?

 

[RogersJetboat454]

Re: engine swap

Yes post alota Pic's......Is this 5 - L.... a FORD?

Uhh... If it's 188, it may be!!!

Hope he didn't buy an old Ford...

 

[johnbrennan]

Re: engine swap

Yes its a 5.0l mercruiser with a 188 outdrive...i know its a ford but their almost indestructible..the engine im pulling out is a 1966 3.0l 4 cyl 140hp and it runs like a top but im not sure what year the donor engine but ill know on the 14th

 

[ezmobee]

Re: engine swap

Just be aware that Ford got out of the marine business over decade ago so parts are going to be tougher to find. The block is generic but accessories and manifolds and stuff like that are going to be more difficult than the equivalent GM motor.

 

[RogersJetboat454]

Re: engine swap

To add to what EZ said, It's allot easier and less expensive to get marine specific parts for your 60's 3.0L than it would be for ANY Ford based drive train. This includes Merc, Volvo, and OMC, the latter two using Ford power up till the 90's, and Merc stopped using Ford in the 70's.

You may p*$$ someone off breaking the deal, but IMHO if you want something you can get NEW AFFORDABLE parts for, your better off backing out, and getting something GM based.

 

[randy4140]

Re: engine swap

John, where do you reside? I am looking for the 4 cyl assy you are removing. I am in MI

 

[johnbrennan]

Re: engine swap

Im up in the ottawa valley on the quebec/ontario border..update on project engine is a 5l mercruiser and outdrive is model 888...just waiting on winter to let go and will take pics..btw im keeping the old 3l cuz now i have 2 identical engines which would make a interesting project in the future..