So the 350 in my '87 is tired and old..Most likely it's the original. The PO replaced the transmission-a 700R4 from what I can tell-and I'm thinking it's getting close to replacing the power plant.

I'm planning on using it as a DD for the next couple of years then handing it off to my son when he's old enough to drive. Not planning on any heavy off roading other than trips to the deer lease etc. I'd planned on swapping the 350 for a 5.3, but that's just not possible financially. A local mechanic I know and trust tells me he can build a 400hp 350 for $2000 and based on the price of long blocks and crate motors, I'm thinking this is a good deal. Can the transmission handle that engine, or would it need work too?

 

A properly operating 700R4 with the updates that have come out along the way should work behind a 400HP engine provided it isn't beat on. Without knowing what was done to the transmission previously, that is a big question mark that you won't know the answer to until you try it.

$2000 for a 400HP build is likely using parts from your engine or at least another used engine. Doesn't sound like too bad of a deal.

 

That's a little more hp than I was looking for considering my plans for it and who'll be getting it after I do. Also, the transmission is a rebuilt/reman'd from O'Reilly or Autozone and hasn't been in there very long. I tried to contact the PO and find out as much as I could but he never answered.

 

Provided they installed the latest parts, it should hold up fine for your plans.

You could probably save a good bit of money having your current engine rebuilt.

 

The 700 R4 o/d transmission is a hell of a brute set up.With that much hp in front of the 700 R4 , you will be taking chances.A motor that has that much power/torque would need a stronger torque converter to run correctly, the tranny will have to be built to withstand that much torque.A stock built tranny isn`t made for no more than 300 horses.I wouldn`t take a chance with it.It may leave you behind some where`s.If you have the funds, you can pay someone to rebuild to your specs.Just make sure you have them install the"Corvette Servo and a shift kit!"If you want,you can delete the transmission cooler lines from the radiator,run a new cooler to the front of the radiator.