383 cheap fun build ideas

jumpjets

Petty Officer 1st Class
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Nov 11, 2010
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313
I recently dropped a 383 in place of my tired 6.2L merc MPI motor. It’s running great, but I have an entire 6.2L short block in my garage. I’d like to rebuild it for fun.
I’d like it to have 400-450hp, spin at 4500 RPM all day long, and be on a budget.

can you guys recommend some good reading material or videos to get me started? I’m taking all the parts to the machine shop tomorrow to see if they are junk or not. If I can reuse the block, crank, and connecting rods, that’ll really help with the cost.
 

Scott06

Vice Admiral
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Apr 20, 2014
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Are you in salt water and if so d9 you have closed cooling? Might not be worth putting money into a raw salt water cooled block over ten years old.
what killed the original engine and what did you replace it with ? stick reman?
 

jumpjets

Petty Officer 1st Class
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Messages
313
Are you in salt water and if so d9 you have closed cooling? Might not be worth putting money into a raw salt water cooled block over ten years old.
what killed the original engine and what did you replace it with ? stick reman?

I’m in salt water. I’d upgrade to closed cooling for sure.
Can I run aluminum cyl heads with closed cooling?

I fried the piston rings in my original motor. I ran a poker run last year at 5000rpm for about 5 hours straight. It burned my piston rings and the motor had a ton of smoke and blow by afterwards. I replaced it with a crate 383 long block from ATK. It has a slightly bigger cam than OE, Dart iron heads, and a 4 bolt block. Otherwise it’s about the same.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
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47,306
I recently dropped a 383 in place of my tired 6.2L merc MPI motor. It’s running great, but I have an entire 6.2L short block in my garage. I’d like to rebuild it for fun.
I’d like it to have 400-450hp, spin at 4500 RPM all day long, and be on a budget.

can you guys recommend some good reading material or videos to get me started? I’m taking all the parts to the machine shop tomorrow to see if they are junk or not. If I can reuse the block, crank, and connecting rods, that’ll really help with the cost.
to get 400-450 hp, your RPM on the top end will be over 5500.

define budget? you have a cast crank, not going to survive 450hp too long, however would live at 400hp.

ditch the rods, SCAT forged rods are cheaper than re-conditioning the factory cast rods. check prices on regrinding your crank vs buying new

most likely because you are in salt water, if you have any appreciable hours on the motor in salt, you may not be able to use the block and heads

because you are in salt water, your heads and block have rust scale in them. no amount of mechanical/chemical/baking cleaning will get that out and you will foul the heat exchanger. I am using just a set of heads that were run in salt water for a very short period of time. the heads were acid soaked, then mechanically cleaned and then baked by the machine shop. I installed a screen to keep any of the chunks from getting to the heat exchanger. I have plugged said screen on 8 of the past 9 trips with small bits of rust coming out of the cooling passages of the heads. save yourself the frustration, either keep your motor and run it as raw water cooling, or go with a new block and heads.

yes, you could run aluminum heads with closed cooling

brand new parts to build a 377 will run you $3500 or so. that is a new GMPP block, new scat crank and rods with KB pistons, new GM vortec iron heads, new comp cams K-kit and new melling oil pump.

if you want good aluminum heads, add $600 to the price above.

if you want a forged crank and forged pistons, add $500 to the prices above

if you want to drop a blower on the motor now that you have forged internals, you can
 

jumpjets

Petty Officer 1st Class
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313
Scott, good gouge. Thanks.
Do you really think iron vortec cylinder heads are good enough? I was thinking some super cool Edelbrock performer aluminum heads or something like that.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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yes, vortec heads are good enough unless you want to go away from a budget.

much better heads on the market than the Edelbrock heads.

the stock iron vortec heads with a polished combustion chamber, mild throat work will flow great and not have all the detriments of aluminum heads (such as needing iron valve seats, or the valve seats coming out on long runs)

if you want to make killer power, your looking at AFR's or Darts.

Highly recommended to go with inconnel valves. https://www.airflowresearch.com/190cc-sbc-vortec-cylinder-head/
 
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