New engine opinions

[84TXGN]

What I have:

-.030 bare 109 block
-.030 forged pistons
-484 4.1 block with lots of cracks between the center headbolt holes and the water jackets
-nice forged pistons for a 4.1
-stock .020/.020 crank
-stock rods
-67mm turbo
-fmic
-champion irons
-60# injectors
-dual nozzle alky
-Translator GEN II
-stock intake/plenum/rjc powerplate
-roller cam & girdle (to be purchased after chort blcok is decided upon)

What I want:

A reliable (as reliable as I can get) engine for mostly street use (very spirited street use though) that is capable of pushing a full weight GN at 130-132 mph or so in the 1/4.

SO...

Its either 4.1 or 3.8...stroker or not...steel crank or stock

All opinions welcome. Thanks.

 

[413turbo]

i had the same delima, 3.8 or 4.1- i have both blocks.
mine is a 291 with no visible cracks(the shop is futher checking it now)
i'm doing the 4.1 (i hope) just because i had a cover and oil pan for it.
either one would have been a budget build this time. i really want to go all out on the 3.8, so i'm just going to hang on to it.

i've read, about people running the 4.1 with the deck cracks, but i don't think i would try it.

if you don't do the 4.1, i may be interested in the pistons.

 

[charlief1]

I hate to say it but you just answered your own question. If you've got all the parts use what you have. Advantage of the stroker is torque and cubes. The biggest disadvantage is fitting everything and the rods have a tendancy to hit the oil supply to the pump on the pass side of the block in either engine. Do the one that you think is the best idea. I'm doing a 4.1 with 6.65 corrillos and stock stroke to increase torque that way.

 

[84TXGN]

I hate to say it but you just answered your own question. If you've got all the parts use what you have. Advantage of the stroker is torque and cubes. The biggest disadvantage is fitting everything and the rods have a tendancy to hit the oil supply to the pump on the pass side of the block in either engine. Do the one that you think is the best idea. I'm doing a 4.1 with 6.65 corrillos and stock stroke to increase torque that way.

I'm leaning towards the 3.8, girdle, stock crank and forged pistons/rods. I think that would be reliable for what I want. The only reason I was thinking about a stroker would be if I was going to buy a forged crank it might as well be a stroker.

 

[Lee Thompson]

stroker

Putting a 3.625 stroke crank in a 109 block requires lots of fitting. A girdle adds ever more fitment problems.

 

[49-blues]

i would do the 4.1 with billet caps. as long as the cracks are not a problem.

 

[Rell87]

I have a stage 1 3.8 block with a 3.625 crank. Even though I just payied my builder to put it together I don't think he had any fitment problems. F___ing expensive though.

 

[Rell87]

Oh my bad he said he had a 109 block.

 

[fastdon3]

have you went to the track yet if so whats your times

 

[decarlo sloan]

With that 4.1 having cracks in the block i would do the budget build on the 4.1, I heard of few people on this site runnung 4.1 with cracks and no prob. I also want to do a 4.1 stroker, but will wait to see peoples results.

 

[Dynalow00]

84TXGN- I had this same dilemma - My 3.8 crank was less than perfect, so I went looking for a forged unit. I am now having a 4.1 stroker (4.5L) built that should be lots of fun on the street. My car is full weight and no cage. I intend to drive it 99% on the street, and occasionally get kicked off the track.
My understanding is that the 4.1 makes a great street motor- off-turbo driving is improved and spoolup is excellent. I intend to run 18-20psi and not work the parts quite so hard as well. I am saving my 3.8 for a close-to-stock rebuild as backup.
So I guess even though mine isn't done yet, I would still suggest you go with the 4.1- just find another block. You've got a great list of mods to go with the build. -Steve

 

[fastdon3]

whats your E.T. on that 4.1 stroker