I have a 1976 Cobra Jet tri-hull with a chevy 350 and jacuzzi jet drive. The engine runs but not great, I believe it is the original. I put rebuilt heads, new lifters, pushrods in it. It has a knock from the bottom end. Kinda on a budget (I know, I shouldn't own a boat on a budget...) Now, should I rebuild the bottom end or look for a good used to swap with? But then again, you never know what you are getting, could be someone elses piece of junk otherwise they would be using it...right? I have rebuilt the boat from top to bottom (except for the engine), great shape except for the most important part.

Give me your thoughts if you would please...

Probably wont fit but good idea!

So, a new top end? Lifters replaced, but not the cam? What heads? (casting #'s?)
Where do you want to end up?

Tough choice-
 1)  Rebuild bottom end-
      Summit and Speedway have cranks for cheap, resize rods and all new bearings, rings, oil pump, cam, and throw the heads back on.

 2) stroker kit-
       Again, there are deals to be had on a 383 kit, but now you are gonna bore the block, resize rods, mod the bottom end for the stroker crank, etc

3)  Get a reman vortec short block w/ roller cam. (suburban/pickup, 5.7, $695, ebay)
        You will need a decent list of parts to make this work for you-
         a. roller lifters, dog bones and spider
         b. 1PC rear main oil pan
         c. PTO adapter for 1PC rear main crank
         d. Shorter (for roller) push rods
         e. Decent 64cc heads, or smaller chambers.
         f. and if you dont have one, an aluminum intake, and decent carb.

4)  Find a $200 takeout 350 and run the dogsnot out of it, fingers crossed. (New paint and chrome always makes 'em run better )

What rpm's were you seeing out of the old motor? Do you know what impeller is in that WJ?


Dan'l

I hope you didn't spend hard earned money on the 882 heads. Probably one of the worst sbc head available, 76cc's, about 7.8:1 Compression 

If you are gonna put a crank kit in it, its time to remodel that 350...

1) crank kit* and oil pump   (crank $190)  http://www.summitracing.com/parts/esp-103503480/overview/make/chevrolet
              oil pump $24 http://www.summitracing.com/parts/sum-121155/overview/make/chevrolet

2) decent double roller timing chain $29-  http://www.summitracing.com/parts/sum-g6600-9/overview/make/chevrolet

3) a little cam $104-  http://www.summitracing.com/parts/sum-k1103/overview/make/chevrolet

4) Some 64cc heads (I have some swirl ports, they work decent to ~4600 rpm)  Comp ratio ~9.3 - 9.4:1

5) a garage sale intake manifold ~$25

6) button it up with a gasket kit, 30 bux, http://www.speedwaymotors.com/Speedway-Small-Block-Chevy-Overhaul-Gasket-Set-350-Chevy-67-85,3208.html

*need rings, rod and main bearings


add a decent holley, and gm hei, 325 hp for miles and years  


Dan'l

I paid $20 for the heads. The heads that were on it are 462624, I still have them.

scrap steel prices right there
624's ans 882's should be used for door stops and anchors
there are some 305 heads that are better (53 to 58cc chambers)

What manifold do you have?
GM HEI?

Dan'l

Run it, till it don't run no mo!

I think thats the best advice yet! Thanks Beerjet!