Anybody here with a big block in their 2nd gen? I have the oppertunity to buy a rebuilt 454 for $1200 and am seriously considering the swap. The front springs already sit high. Are there any major issues with the install?

 

I've got a 427 in mine and have done numerous SBC to BBC swaps. It's very easy. Try the search function and you'll see lots on the swap in 2nd gen forum.

 

I figured it was one of the easiest swaps. (i did a V8 into our Astro van once). I'm gonna do it soon so, i'll keep ya all posted with progress. Thanks!

 

Reuse the smallblock motor and frame mounts, and if you've got AC it will need to remove the box, or swap to BBC early 2nd gen box and core.

 

Also depends what transmission you're using. A short tail T400 is 1/2" longer than the 6" tail T350. Unless you have more than the standard amount of end play in your present slip yoke, you'll need to have your driveshaft shortened if you keep the small block engine frame mounts. T400 slip yoke needs to be swapped in anyway, the splines are different. However, using the big block frame & motor mounts moves the engine forward a little under an inch (as well as over to the right), which means you wouldn't need to shorten the driveshaft.

 

I appreciate the responses. I've never done the small to big block swap, but, heard it was one of the easiest there was. Didn't even realize the motor mounts were the same. I'll be doing it so, i'll keep ya posted when i start (as soon as this Northern NY weather breaks for the good).... i'm an old school driveway mechanic (LOL)!

 

The b.b. and s.b. motor mounts aren't the same. You may need to "improvise", depending on your setup.

 

Camaro69, do you change just the block mounts or frame also? Not a problem anyway (i'm a retired machinist/welder) i can fabricate most anything metal. And... i'm gonna use a 5 spd tranny (1989) with the hydro clutch, make my own tranny crossmember and add subframe connects. My next issue might be, can i use the SB flywheel and clutch assembly?

 

It would be as a set, brackets and mounts. There are differences in the width of the frame horns, as well as the cross-bolt hole to top of bracket dimension. The mounts and brackets aren't all a mix and match as you please. Now, 1971 did say you could use the small block setup, as he did on his car. If it were mine, I would do some trial fitting with the small block mounts and see how she fits. But if you run into some valve cover to brake booster, exhaust to steering box, heater core inlet/outlet to valve cover, or carburetor to hood clearance issues, you'll need to look into the b.b. brackets and mounts.
As far as that 5 speed behind your big block...don't wanna do that! GM didn't even put a 350 in front of one of those transmissions for a reason. A b.b. would blast it apart in no time.

 

Then i guess i'll have my 700r4 rebuilt and beefed as needed because i will not go without an overdrive. I figured that if i don't use drag tires, i'd break the rubber loose before the driveline was in danger. Thanks! Everything will be kept in mind.