1990-91 454 - Which Flexplate?

[blast]

I have to change the flexplate on my truck, it's chewed up from a bad starter install.

Engine is: Casting# 10069286...454.......1990-91...4-bolt, Mark IV, Short deck.
Transmission: TH350

Which flexplate should I use for this, is it supposed to be weighted / externally balanced?

Would this one work: http://northernautoparts.com/ProductModelDetail.cfm?ProductModelId=17691

Thanks.

[VileZambonie]

Any autoparts store should be able to tell you the proper flexplate to use.

[blast]

Any autoparts store should be able to tell you the proper flexplate to use.

That's never fun when your vehicle is made up of a number of different year parts.  Like mine, 85 body, 91 engine, 86 chassis, old th350, and a really old NP203.  So when I need engine parts, I have to find a truck model/year that had my engine in it, and there isn't any.  Then they get all goofy with me and won't help me anymore. 

[VileZambonie]

Match the flexplate to your year engine and just verify it has the same bolt pattern to your torque converter before you install it.

[blast]

Finally swapped out the flexplate, and just to follow up:

Apparantly there is a difference between the mk IV 454 and the gen 5 454 flexplate.  Both externally balanced (normally external, I guess internally balanced 454s are rare because they require different crank and pistons so the balancing can fit inside), but the gen 5 454 uses a different weight on the flexplate.  I hope GM made it so you can't accidently bolt the wrong flexplate on, they both have 6 bolt holes and a peg hole.  I got the right one on mine, but I'd hate to see someone else put the wrong one on someday. 

My 90-91 was the last production year for the mark IV engine, and a lot of vehicles from that year used the gen 5 engine.  So asking the clerks at most of the local autoparts stores was useless, none of their databases could tell the difference in the flexplates.  Online it isn't so hard, they tell the engine model.

Something funny, I didn't know the th350/np203 was perfectly balanced on the crossmember, lol.  We clamped a flatstock drop catch under the frame to lay the crossmember on, about 2 inches below frame rail, and just lowered the tranny/transfercase onto it, secured it a bit, and left it there until the flexplate was changed.  Worked very slick.  And everything is A1 again.  Just in time for big snow.