BBC swap questions

[sls_06ion]

I'm kinda new to the forum, and kinda new to playing with old trucks, playing with sport compacts for a few years now. I'm fairly familiar with these truck as I've been doing quite a bit of electrical work, HVAC, and audio, plus I can turn wrenches too. Now to my questions I've been give a 454 and a th400 tranny they have 37xxx miles on them don't smoke no blow by, tranny shift fine so it can be done with a little cleaning of pair - now the harder part, I've got a 66 GMC 1/2 ton 2 wheel drive--351 v6 and a 4 spd manual. I'm curious as to what parts I may need to aquire to do the engine/tranny swap. I have a set of motor perchs for a small block, are these what I should use? and since I have a manual tranny currently, should I order something like the CCP tubular tranny cross member w/ prothane style mount? Does the firewall need to be "manipulated to fit" a BBC? What kind of shifter has anyone used after a swap like this, as I currently have a floor shift?

Any body have any helpful hints or suggestions?

I'll try to update this post with some pictures later on of the truck and engine bay.

thanks everyone, Tony

[Captainfab]

The original style motor mount stands will work for the big block, although I prefer not to use them. For the trans mount I always just use a factory mount from a '67-'87 pickup. It doesn't matter if it was for a TH400, TH350, or 700R4 it'll work just fine. You shouldn't have any issues with firewall clearance as long as yopu stay with factory short valve covers. For a shifter, any aftermarket cable type shifter would probably be the easiest to deal with. Are you going to use the factory exhaust manifolds or go with headers?

[greg64]

Howdy in Boise! I wanted to ask that you post on this site: http://www.6066gmcguy.org/ when you remove your existing 351. The guys over there are into the GMC V6s and would no doubt find a home for yours.

There are a number of guys running big blocks on this forum. What I've gathered from that is the BB fits without massaging the firewall (tight around the passenger side valve cover). You may need some fore-aft adjustment for the fit before you lock down the new motor mounts.

Good luck.

[1gearhead]

The BBC swap is pretty straight forward. Position the engine far enough ahead to get clearance for the RH valve cover. After market tubular type motor mount brackets seem to work the best. We usually fabricate our own. An after market trans crossmember can be purchased or modify and reposition the existing crossmember. Here again we often fabricate our own design. Simple enough to do. The rest is pretty straight forward hooking up the linkages, wiring, plumbing, etc. We have done several with out encountering any real problems.

[sls_06ion]

thanks guys, so as far as motor mounts do you have any suggestions as to where I'd be able to find a set?

greg64 - definatly, I want this motor and tranny to go to someone that has the desire for one of these 351's!

anyone have any other suggestions or helpful hints?

[NF65Fleetside]

This is a topic thats been gone over tons here on this thread, you can do a search and come up with some descent writeups and info. A lot of guys have gone different routes with the install, as in using complete front clips, aftermarket mounts/perches, etc. I have a write that you can check out, http://http://67-72chevytrucks.com/v...d.php?t=279769

I went with the V8 tubular mount/perch kit, TH trans cross member and mount kit from the Truck Shop. Same as the kit from Brothers and CPP but almost $100 bucks cheaper! Only slight frame rail notching is needed and if you use the same headers that I did, Summit Racing full length for 68-82 truck/suv's....its pretty much a drop in affair. Listen to 1gearhead, he completed the swap on my truck and knows his stuff. If your familiar with wrenching and mild modifications then you can knock out the swap in a weekend. Good luck and keep us posted!

[sls_06ion]

Thanks, I'll look at the link once I get home, thanks for the info, I used the search but I think it owned me as I was probably not using the proper terms.
Thanks Again Tony

[protrash64]

I considered this for my burb and actually bought the stuff to do it and got rid of the engine.

........use the small block mounts is one way to go.

.......use original BB mounts from 67-72.........expensive.

......use mounts from 73-87 truck......cheap. You will have to clearance your frame similar to either th 67-72 trucks or the aftermarket mounts to use these factory mounts.

I dont know about the exhaust issues.........