mtwoolford

I'm rebuilding a 96 LT4 350.

I'd like to use a forged steel crank in it with the stock 3.48 inch throws. Well low and behold, almost all aftermarket forged cranks are for a 383 with 3.75 inch throws.

One of the few aftermarket cranks with the stock 3.48 inch throw is made by EAGLE, part number 435334805700 (summit p/n ESP-435334805700);

Anyone have any experience with this crankshaft? And more specifically with one in an LT engine (Gen II) since it is represented as a crank for a GEN I engine (1986 - 1991)?

Any advice is appreciated.

rklessdriver

Should be Eagle PN 435334805700.

I helped a guy with a cam and cyl heads that used that crank in a 355 LT1 build. It worked fine.

It's designed to be straight up internal balanced (front and rear) so you either have to run a neutral FW or you are going to drill a crap load of weight out of the rear counterweight when balancing it.

Scat also makes a few 4340 Forged cranks that will work.

PN 4-350-3480-5700-L (51LBS) STD weight - Internal/External just like the factory balance.

PN 4-350-3480-5700-L-2 (48LBS) Light weight - Straight up Internal balance.

PN 4-350-3480-5700-L-3 (46LBS) Ultra Light Weight - Straight up Internal balance.

You could aslo run a 3.5" stroke which is availiable if you wanted.
Will

mtwoolford

I edited my original post to reflect the correct part number. Thanks

mtwoolford

I'm building this engine around 6 inch rods and aftermarket pistons; my flywheel is a SPEC light weight billet steel flywheel with a bolt in counterweight. When I ran this flywheel on the stock oem engine there were no problems, but since I'm putting together a mismatch of parts, the plan is to have the entire lower end, harmonic balancer to flywheel balanced as an unit. I believe (hope?) that removing the counter weight will simplify balancing the lower end.

rklessdriver

I would remove the weight on the flywheel.

Any of those cranks should straight up internal balance with no heavy metal using 6" rods and fairly light pistons.
Will

C409

.... I have a factory Forged Crank with a One Piece Rear Main Seal ... a couple of journals are pretty rough so it would likely need to be turned down ... casting # 14088532 ... PM me if you have any interest .....

mtwoolford

Thank you for the information; I never knew. It was kind of you to make the offer. Budget willing I hope to use a new forged crank, but if not, a day or two at the u pull it yard looking for a 14088532 is certainly an option. I had the stock LT4 cast crank ground, and it wasn't too expensive, so that option is there also.

Thanks again. Mike