I have a 1974 350 block in my car (2 piece rear main seal). i am in the process of changing my 700R4 to a 5 speed.

i have an old 1 piece flywheel laying around, i know i cant use it, but why is the flexplate that came off my engine, and the 1 piece RMS flywheel such different sizes? (see pic)

do i have to get a different starter?
will the new 2 piece RMS flywheel be the same size as the flexplate i just took off my engine?

 

 

That's beacause the flywheel is a 12 inch flywheel (actually 11. something) and the flexplate on your motor was 14 inch. You cannot use a 14 inch flexplate on your motor, so your best best is to get a flywheel from an 83-86 305 Camaro motor. Or in other words you will need a two piece rear seal 12 inch flywheel.

 

will my starter still fit?

 

size difference is as stated above, autos can use the big flexplate (168tooth/14in dia)

the t5 bell housing, will not clear the large diameter so you must use the small dia, 12 3/4in, 153tooth flywheel.

as a consequence of the size difference your existing starter will not work, and you'll need to get one for an f-body with a 5 spd

since your motor is a 2 piece rear seal, you would need the small flywheel to be for the 2 piece, finding one in a junkyard could be time consuming and difficult, at least for me it was so i wound up going to this website,

www.car-part.com

search for a vehicle that would use the flywheel you need, such as an 83-86 camaro/firebird. the site automatically cross references other vehicles, and gives a listing, the you contact the business that has it. wonderful website, more or less a giant classified add, for thousands of junkyards accross the country