Newer motor mounts ?
 

My 67 GMC C15 has a 250 six cylinder in it.. I'm wanting to put a 350 8 have in it instead. It has the 4 speed truck transmission in it. I have read about moving the mounts forward and swapping sides and the engine will fit just sits back farther. I really want to use the newer clam shell type mounts. I heard something the other day about using the 73 and up mounts.. does this work with out moving the transmission?

Re: Newer motor mounts ?
 

Yes and no. You'll have to keep the transmission in solid, bolt the engine up with the mounts bolted up and set the assy down to see where it mates with the frame. Mark the holes, remove for access with a drill and shim between the frame and frame stand so the stand doesn't twist or lay crooked when it all gets cinched down. Bear in mind that putting the V8 in the 6 cyl position will set the V8 damn near up against the firewall and may interfere with an HEI being present as in rubbing against the firewall without additional clearance. Personally I would elect to keep the 6 and hot rod that for the coolness factor. Still get ya around and good on mileage for the days to come

Re: Newer motor mounts ?
 

Thanks for the response. I do know about the clearance issue and may just run points or something else for now.. I just don't want to mess with getting a different driveshaft at this point because down the road I will change the transmission..

Re: Newer motor mounts ?
 

I put in a 350 from a 79 to a 66 and as I recall just bought new mounts for a 79. I think if the holes were another 1/4" back the HEI would not have fit. Still using the original transmission and two piece driveshaft.

I had a th400 transmission with it and wish I had done the extra work of putting it in at the same time. I let the transmission go cheap to a guy putting a big block in an International.

Re: Newer motor mounts ?
 

Well the early mounts and later mounts are different style. On my truck there is one bolt that holds the engine to the frame mount. The later is a clam shell mount that slips over the frame mount. I will have to do some research on the bolt holes

My main concern is safety of the mount coming apart. And I don't want to use a cable around the manifold or header

Re: Newer motor mounts ?
 

Are you going to use the original style throttle rod and bellcrank or switch to a cable type pedal?

Re: Newer motor mounts ?
 

I think I will convert it to a cable.

Re: Newer motor mounts ?
 

Then just use te original style mounts.

Re: Newer motor mounts ?
 

Thats what I did, original style mounts, but went with a prothane (urethane mount). If you are running a points , or other small cap dizzy you wont have any issues with firewall clearance. The HEI will also fit.....but you may need to take a BFH to the firewall to clearance in I6 position;). Any ? on the bell crank/linkage......you can PM me & I will give you my cell number.....I can talk faster than I type:lol: Best of fun....CrazyL:chevy: