Bellhousing bolt up??

[captjim]

Hey guys, new to the site. I bought a nice 82 S-15, great body, trans, and interior, worn out engine. I have build several Oldsmobile hotrods, but never done this swap. I was wondering if the bellhousing of the original transmission with the 2.8 bolts up to the small block?? Thanks, JIm

[big dave]

nope, the 2.8 is a 60* angle motor, and the 4.3s and small blocks are 90* motors. It wouldn't last behind a small block anyway, even a mild one. Too much torque. The lowest power small blocks have almost 300ft-lbs of torque, about twice as much as a 2.8.

[captjim]

I thought so, but wasn't sure, thanks. What is everone using? TH350's or the overdrive 700's?

[Mike]

if you can get it get one with overdrive
TH350 is nice, but if you plan to drive it often go with a transmission w/OD.

[Dimemaster]

TH350 has less gear ratio spread, is stronger if you plan on a hot rebuild, and is $1000 cheaper to set up.

700R4 has very low 1st gear and a very wide gear ratio spread which can make staying on the torque curve difficult with a motor with a radical cam.

If you want a strip only or hot street/strip truck, the TH350 is a better bet. Better durability and quicker in the 1/4 mile. If you want a mild street driver, than the 700R4 gets the nod--the lower 1st gear ratio will allow a quicker launch than a TH350, a mild engine will have a broad enough power band to not be bothered too much by the wide gear ratio spreads, and the overdrive and lock-up convertor will return good efficiency while cruising.

You can't have a really hot smallblock automatic AND 20+mpg efficiency at the same time unless you spend a ridiculous amount of money. Pick either max performance or max efficiency and build to suit.

[67Truckin]

A properly built 700r4 can hold 500 horsepower without problems and still give you the overdrive option for highway usage. Think Corvette which use better servos, bands and block upshifts into overdrive when under hard power. This has become an extremely popular swap for early hotrods with the higher number rear axle ratios. Good luck on your build! :)

[Dimemaster]

A properly built 700r4 can hold 500 horsepower without problems and still give you the overdrive option for highway usage. Think Corvette which use better servos, bands and block upshifts into overdrive when under hard power. This has become an extremely popular swap for early hotrods with the higher number rear axle ratios. Good luck on your build! :)

The rebuild kit and convertor necessary for a 700R4 to hold 500hp costs more than an entire TH350 setup, including the cooler and core. The new gear sets to cure the wide ratio problem cost $2000. You can set up a TH 350 for $1200 easy, but a 700R4 that will hold 500hp safely and not have the too-wide gear ratios is more like $4000. If you're racing you don't need overdrive, anyway.

[Duckbutter]

I have a stock carbed 350 with a th350 and shift kit I was thinking about changing to a 700r but decided to just put the money into the paint and body fund.This will save on fuel costs if Ilimit the driving to car shows or cruise ins ;)