New member, have questions about my 1973 pontiac ventura

[Swazafix]

Hello everyone, my name is Steve and I live in Marshall IL. I picked up a 73' Pontiac Ventura 4 door in town late last year because I needed something I could pack the kids in, I used to drive an 81' el camino and when my daughter came I had to find more room for my daily driver.

I picked her up for 900 and I have about 80 in her. Had to replace my cap and router, some vacuume hose, radiator heater hose, and an oil leak I still need to fix.

I was talking to some friends at work about engine swapping and someone mentioned some pontiac transmissions will bolt straight up to a small block chevy. Anyone able to help me figure this out?

Its currently running the stock engine and tranny, 250i straight 6 with a 3 speed manual transmission (three on the tree) any help would be greatly appreciated!

 

[melsg5]

you mean a small block chevy to the 3 speed manual or something else. The 250 is a Chevy engine so it should have a Chevrolet bolt pattern. A Chevy small block will only bolt to a Chevy transmission. A Pontiac V8 will only bolt to a BOP(Buick, Olds, Pontiac) transmission. There are adapters available to interchange them. Looks like a clean car, good luck with it.

 

[Swazafix]

you mean a small block chevy to the 3 speed manual or something else. The 250 is a Chevy engine so it should have a Chevrolet bolt pattern. A Chevy small block will only bolt to a Chevy transmission. A Pontiac V8 will only bolt to a BOP(Buick, Olds, Pontiac) transmission. There are adapters available to interchange them. Look like a clean car, good luck with it.

So the 250i engine that came with it stock is a Chevy engine? And my tranny must be Chevy as well? If that's the case, what are my options to bolt straight up? I'm not really a Pontiac guy, but I assumed it was a Pontiac engine. I'd like to put a SBC V8 of some sort if the tranny will take it, I'm just not sure how to go about figuring out the tranny since I couldn't find much information online like I have been able to with other cars.

 

[melsg5]

look at the manual 3 speed GM trani's to identify what is currently in the car

http://www.drivetrain.com/parts_cat...rans_reference_gm_3_4_5_and_6_speeds_v24.html

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[Swazafix]

Hey thanks for this information, looking at the website it appears there is only 2 transmissions it could be.

SAGINAW 1966-81 Cars, 1966-87 Light Duty Trucks:
Cast iron case and extension housing with 7-bolt side cover. Fully synchronized with 30 tooth synchro rings. 1966-69 units may have electric overdrive. It has a four step cluster and all the gears are helical cut.


MUNCIE (Heavy Duty)
Cast iron case and extension housing with 7-bolt side cover. Fully synchronized with 36 tooth synchro rings. This is the only GM 3 speed with the same bearing front and rear. This transmission is found in performance applications.

I'm going on a whim here since its raining outside right now, I'll check for an RPO code later to verify, but I imagine a mid-sized compact with a straight six did not probably come with a heavy duty transmission, so I'm guessing Saginaw 3-speed is what is in it.

This is very exciting, how do I go about finding what engines can mate up with this tranny?

 

[Zimgxp]

A 5.3 and a 460LE would work nicely

 

[melsg5]

I would say any first generation small block but contact these people to be sure.
http://www.drivetrain.com/parts_cat...rans_reference_gm_3_4_5_and_6_speeds_v24.html

On the other hand you could do what ZIMGXP suggests and replace the trani with a modern 4 speed automatic

 

[92 Sunbird LE]

You could put a Pontiac motor in there with the correct mounts and bellhousing and flywheel. A mild Pontiac 350 or 301 would hold up to the light duty 3 speed you have.

Easy way out is a 283-307-327 or a "mild" 350 Chevy V8 in there as these cars came from the factory with them from 71-72. You will need an engine with the provision in the block for the clutch pivot and the crank drilled for the pilot bushing .

Everything should bolt right in using Nova V8 mounts. ( frame ) V8 holes in the front crossmember should be there already.

You could paint the Chevy engine Pontiac Blue to fool everyone....

Doug in P.R.

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