Thread: 383 Marine Build

Tweet

I am considering updating my SBC 350 in my boat to a 383.
It's already bored 0.030 over and has vortec heads on it and a roller cam.

I would like to replace the rotating assembly with a Stroker Kit.

Not looking for tons of HP (350 would be fine), more interested in torque.

Any suggestions on the rotating assembly? Want to keep compression down to use 89 octane.........gas is expensive on the water!.

How about the machiningclearancing? Can I do this myself with a hand drill? The engine has very low hrs on it so the cylinders won't need to be touched.

you have to have the block machined possibly to clearence the crank, but some do, some don't, and I don't think a hand drill would be a good idea to do that. keep the compression below 9.5:1 and you could run 87/89 octane

Typically, interference occurs at the rod bolt heads/cam lobes in three or four places and at the pan rail/rod big end. Also pay attention to the clearance of the rod small end balance pad at the underside of the piston crown to make sure the balance pad clears through the entire arc. I don't like using 6" rods on these stroker combos because the pin ends up in the oil ring groove. 5.7 rods will work fine.

If you're doing the work yourself, just trial fit everything, then take it apart for grinding. Shoot for 0.080" clearance everywhere and yes, you could use a hand held drill motor with rotary stones or carbide burrs to do it. I've managed with less through the years. If using press-fit rods, take an old wrist pin and sand down the od a few thousandths in somebody's large drill press or lathe. Make it so that it will slip through the pin end of the rod and use this old pin to check balance pad/crown clearance on all the piston/rod combos before you assemble the motor with the press fit pins.

There are two ways to balance the assembly, internally and externally. Externally uses a 400 harmonic damper and flexplate that have built-in weight eccentrics. Internally uses a 350 harmonic damper and flexplate that are neutral balanced.

I'd build the motor with 9:1 c.r. and a 0.035" to 0.045" squish, using a compatible cam to match the 9:1 c.r.

any suggestions on a rotating assembly?

It seems like everyone and his brother are assembling kits these days, but the two most popular are Eagle and Scat. Here are some 5.7 kits.....
http://store.summitracing.com/egnsea...rdSearch#rstop
http://store.summitracing.com/egnsea...=KeywordSearch