trans and cam help

[Morgan72]

Hello all,
first a description of my ride.
1972 GMC c15 a/c cab 350 with a 350th auto trans single track rear axle, all stock.

what i am doing.
first the rear end is now a posi 373 gearset.
want to use a 700r4 trans.
want to use new roller cam with a nice lope to it.

so what info i need to know is...

with the 700r4 i know some were modulated overdrive and some were electronically locked in overdrive.

What type should i use?
are there certain years i should look for?
any other info that would be helpful to selecting the right one for my project?

and for the cam.

what should i get?

want a roller rocker set up, and everything else remains stock...stock ram horns, edelbrock 600 carb, stock fuel pump.

any help would be greatly appreciated.

have a good one and thanks
shaun

My 700r4 is out of an '87 S10 Blazer. You want '84 or newer. You can just run a switched 12v source to lock up the converter manually, or use one of the kits available that use a vacuum reading to signal when to lock it.

For the cam I recommend https://www.compcams.com/xtreme-ener...all-block.html
or
https://www.compcams.com/magnum-215-...all-block.html

I like the second one most. It makes tons of torque, which you need in our heavy trucks. A buddy had it in his square body stepside and it ran 14's. Would easily smoke the tires and had a slight lope. It was his driver at the time.

Good luck!

[Accelo]

Use a 1987 to 1992 700R4/4L60 core. Forget the earlier Transmissions. Not worth messing with. I see you do not have a 4 Wheel drive. So I am assuming something close to stock tire height. The transmission will work fine for you conversion. With out headers you will only have to move on of the transmission linkage where it bolts to the frame and slightly adjust the linkage and your good there. If you had an automatic in it the cooler lines will also line up will the slightest of tweaks. Moving the stock automatic cross-member is also easy enough, just drill some holes in the new location. Shorten the drive line and your in business. Just so you know in 2000 a Stock Silverado had the same 4l60E with 3:73 ratio. To do it right you will have to add the dual function brake switch. Lots of information on how to wire it on the internet. Converter selection with a cam may be the most difficult item. Way too many opinions. Call you favorite converter company with the motor displacement and cam specifications. Then use their recommendation!

Remember the Blazer 2.8L motor's transmission takes a different case and will not bolt up.

Based on my trans guy's recommendation, I used a 4.3 converter. It stalls higher than stock behind a V8. I have a 454 that makes 500ft/lbs of torque and it stalls at about 2700. With the 350 it should be 22-2400. That will be good for a driver with the cams I noted above. Much less expensive than an aftermarket converter.

[jimijam00]

does the exhaust, intake, and heads have to remain stock? if so, i recommend skipping the cam and 700R4 and just run what you brung. spending the time and money on a few miles per gallon just isn't worth it in my book. that's my two cents.

[Morgan72]

ACCELO very helpful thanks for the info and insight on the dual brake switch thing and the converter...i never knew.

[Morgan72]

LOWRIDIN67 thank you will check into those cams. and the torque converter info as well