98 vortec flexplate to th 350 transmission

[keith nohner]

I just installed a 98 vortec 350 out of a wrecked 2500 chevrolet. I switched it to carb with a weiand stealth intake, everything was going good till I realized that the flex plate holes dont line up with the converter. The vortec motor had six bolts, the th 350 has three. I realized this, but I just figured three of them would line up. Which newer one piece rear main seal flex plate will I want to get. Sucks I already tightened the bell housing bolts, but At least I wasnt any further.

[trac209]

If you have an angle drill you may just be able to line up the converter to a place on the flex plate where it's in a balanced position in relation to the other holes and drill the plate to match the converter. Pulling the starter out might give you enough space. I have had to do that
On occasion and it's worked. Good luck.
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[hugger6933]

Do three line up or just get close ? It has happened to a lot of us many many times to have to grind out a fly wheel to bolt up a converter. As long as you stay within reason [say the dimpled pad if it has one ] I say you will be fine. That intake you used is it a single plane or a dual plane intake? That vortec motor in that truck will be qite peppy you will be pleased and if not add a lt4 cam or somethime equal and it will really wake up. Jim

[FirstOwner69]

I think most aftermarket flexplates (external balance for 1 piece seals) are drilled with dual bolt patterns and are available with 153 or 168 teeth. I just installed a TCI #399773 168 tooth from Summit Racing on my GM Preformance Products Vortec block crate engine and TH400. I have not yet started the engine. I removed a brand new 153 tooth GM flexplate from the engine that appears to have a 10-3/4" 3 bolt pattern. I don't see a part number on it, but can try to find one if that's what you need. Take a look at Summit's catalog for more choices.