3.8 or 4.1 advice

[TurboToy]

i have both blocks and can go either direction both are ready to go to the machine shop to be cleaned and have steel main caps and girdles be put on. my only thing is the 4.1 is the 82 model and the turbo i am looking to go with is 72 or 74 with 83lb injectors and a large front mount looking for real low 10's or 10.5's for brackets. i have all the pieces for both which shold i spend the money on and finsih completing.. thanks in advance for any advice or been there done that history..

turbotoy

 

[CTX-SLPR]

You seem pretty setup to go either way, though you must consider one thing, Pistons. Custom Forgings for a 4.1 are about 1.25-1.5 times more expensive than the off the shelf pistons for the 3.8. If you are willing to pay that money, go for the cubes, if you aren't, stick with the 3.8. Also if you have a 109 3.8, it will be stronger than the 4.1 therefore potentially cheaper in the long run. I'm going to be running an 84 4.1 so I love my cubes but then again I paid almost $600 for my pistons, pins and rings.

Just some food for thought,

 

[sixgun86gn]

Well i wouldn't bother with that 82 4.1 the oiling passages are not as good.

I used an 84-85 vintage 484 casting block and it was bored.055 for some used pistons I bought out of a stage 2 motor.Final bore was 4.020 beleive it or not.

Never ran hot,made bucketloads more power than my 3.8 at less boost.Ran 127 in the 1/4 on 20# from a t63.The 3.8 never made better than 123 mph with all the same stuff at 25#.

The 3.8 is definitely cheaper unless you can find used parts for cheap.I built my shortblock for around $800 and it handled 500 rwhp/500rwtq all day.

 

[Whitettype86]

Forget about the 82 4.1 block stick with the 3.8. And u can build a budget 4.1 with ford forged pistons and chevy 3.1 rods and u would also have 2 extra pistons. I would stick with the 3.8 turbo motor the block is stronger then the 4.1. Its all up to u

 

[TurboToy]

thats what i was needing to know and was in the same thought as the past replys the oil was goin to be a proble and the block was weak.. thanks again guys.. turbotoy

 

[getchasum]

Forget about the 82 4.1 block stick with the 3.8. And u can build a budget 4.1 with ford forged pistons and chevy 3.1 rods and u would also have 2 extra pistons. I would stick with the 3.8 turbo motor the block is stronger then the 4.1. Its all up to u

Have you got all the info on the piston and rod combo, all specs, part #'s, procedures, etc....

interesting....

 

[ijames]

Dave Williams on the gnttype list pointed out several years ago that you could use 3.1 rods and Chevy 383 stroker pistons (don't know which Chevy rod you were supposed to say you were using), but I've never heard of using Ford pistons. Please give us some more details!

 

[BandAid]

Well i wouldn't bother with that 82 4.1 the oiling passages are not as good.

I used an 84-85 vintage 484 casting block and it was bored.055 for some used pistons I bought out of a stage 2 motor.Final bore was 4.020 beleive it or not.

Never ran hot,made bucketloads more power than my 3.8 at less boost.Ran 127 in the 1/4 on 20# from a t63.The 3.8 never made better than 123 mph with all the same stuff at 25#.

The 3.8 is definitely cheaper unless you can find used parts for cheap.I built my shortblock for around $800 and it handled 500 rwhp/500rwtq all day.

SixGun86you sent me a buch of info on doing the 4.1 hope I still have the info,,but none the less---Sell me your dam motor :tongue: :biggrin: :biggrin: :biggrin:

 

[sixgun86gn]

Can't sell it,traded it for a 70 skylark to build a GS clone.

Had to make room for the new aluminum version. :biggrin: