[rdweddle]

I am in the process of putting a new 350 crate motor in a 1970 Pontiac Tempest with a 6 cylinder motor currently. The new motor is an old style 57-85 GM Crate engine. What options would I have for motor mounts? Do 70 chevelle body mounts fit in the A body Pontiac?

[SteveGB21]

Much work will need to be done.

1) The coil springs for a Chevelle will need to be obtained. They have options such as V8, small-block and A/C vs Non-A/C.

2) A bigger radiator will be needed.

3) Wire lengthening or shortening.

4) Frame mounts from a '68 to '72 Chevelle/Malibu/El Camino.

5) Radiator hoses for the Chevelle (or the universal flex hoses).

Did a swap from a Buick 231 V6 to a Small-Block Chevrolet 305. These were some of the things I had to swap.

Luckily with the 250 L6, you won't have to change the fuel line. I would strongly recommend if your brake lines are shot to do it now while the engine is out of the car. On the belt system, are you using a serpentine belt? If not, try to get all the accessory belt drive in one buy. 69 and later SB Chevy's use the long style water pump. Most don't have the smog pump, but have the TCS setup for the 70-74. 73 used EGR. 75 used catalytic converters. Some things to consider. The wires may have the TCS. Check with state laws requiring emissions. Good luck on your project. SB Chevrolet's have many opportunities. You could even go with the LS series later on.

It doesn't bother me, but this may irk some Pontiackers. Since this was originally a Chevrolet powered car, nothing wrong with this swap. I did it on a 77 Buick Skylark. Not fond of Buick engines at all.

[SteveGB21]

Forgot to mention this on the transmissions.

What do you plan to have? I wouldn't recommend a Powerglide.

Go with a TH-350 with the 6" tail from a '75 and later model if you bypass the TCS (Transmission Control Switch). If you need it, look for a '69-74 case. The Chevelles, Novas, and Camaros all have the 6" tail of the TH-350. Probably the Monte Carlos may also. Not 100% certain. Impalas, Trucks, and Vans, as well as the wagons have larger tails (the 9" and 12"). The Blazer/Jimmy and K-series trucks don't have a tail due to a transfer case in place.

The TH-400 is more of a heavy duty. If you chose this one, go with a 4" tail. However, the driveshaft would need to be shortened. The yoke would also need to be changed, transmission crossmember moved a few inches downward, and the emergency brake cables relocated. A Chevelle SS/GTO would work.

Then, there are the overdrives. The 700R4 and the 200-4R can also be used with a cable, unlike the 4L60E and 4L80E transmissions that require a standalone computer.

Or, if it is a manual, can't help you on that one. Sorry. Good luck.

[joeyhunter]

I'm guessing the 6 cyl. mounts won't work for the 350? I'm doing the same swap !

[SteveGB21]

The 250 L6 frame mounts can ONLY use that engine. Frame mounts from a '68-'72 Chevelle/Malibu & El Camino can be used for a SB Chevy. Have corresponding sending units (lights vs gauges). Go with Energy Suspension has the early motor mounts (pre '73), since early rubber mounts tend to break.