Motor mounting question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BD70CST · 10-16-2019, 02:57 PM

So, the big block that came with my C20 needs a rebuild, but I have a newly rebuilt 327 that I can place in here. The way I understand it, I can do this simply by moving the brackets back a hole. But if I do that, the bottom hole won’t line up. Do I need new brackets or do I not need to move them back?

Also, with the 327 and a TH400, I would need a 168 tooth flex plate, correct?

Thanks again. I love this site.

Bob

**LockDoc** · 10-16-2019, 08:20 PM

Quote:

Originally Posted by BD70CST

So, the big block that came with my C20 needs a rebuild, but I have a newly rebuilt 327 that I can place in here. The way I understand it, I can do this simply by moving the brackets back a hole. But if I do that, the bottom hole won’t line up. Do I need new brackets or do I not need to move them back?

Also, with the 327 and a TH400, I would need a 168 tooth flex plate, correct?

Thanks again. I love this site.

Bob

Just get a set of the SB V-8 brackets and sell the '68-71 BB brackets. They can be worth a little coin. If you upgrade your membership to a Premium member on here you can sell them on the parts board.

Here is a thread I and others posted about the differences in the frame mount brackets.

http://67-72chevytrucks.com/vboard/s...d.php?t=732393

LockDoc

BD70CST · 10-16-2019, 08:57 PM

Thank you!

I’d like to keep the big block brackets so I can put the original big block back in one day. But thank you for the reply.

Andy4639 · 10-16-2019, 09:12 PM

I just did this but the other direction. I'm going from a six to a V-8. I moved it and drilled new bottom holes.

**LockDoc** · 10-16-2019, 09:41 PM

Quote:

Originally Posted by BD70CST

Thank you!

I’d like to keep the big block brackets so I can put the original big block back in one day. But thank you for the reply.

No problem.

Yes, if you are thinking about re-installing the BB I would keep them.....

LockDoc

*randy500* · 10-16-2019, 10:47 PM

No need to move the brackets back, the rear position is 6 cyl only. Besides if you did you would need a shorter driveshaft.
I believe the big block brackrts sit the engine up and forward a little...its not much.

**kwmech** · 10-16-2019, 11:57 PM

Just bolt the small block down on the big block stands with the big block cushions. No need to move anything. Center line from the mounts to the back of the block is the same at 16''

**kwmech** · 10-16-2019, 11:59 PM

Quote:

Originally Posted by randy500

I believe the big block brackets sit the engine up and forward a little...its not much.

Moves it forward 1-1/4'' if I remember correctly. Just enough so the cylinder heads don't hit the firewall

10-16-2019, 02:57 PM	#1
BD70CST Registered User Join Date: May 2012 Location: Nor Cal, CA Posts: 17	Motor mounting question So, the big block that came with my C20 needs a rebuild, but I have a newly rebuilt 327 that I can place in here. The way I understand it, I can do this simply by moving the brackets back a hole. But if I do that, the bottom hole won’t line up. Do I need new brackets or do I not need to move them back? Also, with the 327 and a TH400, I would need a 168 tooth flex plate, correct? Thanks again. I love this site. Bob Attached Images

10-16-2019, 08:57 PM	#3
BD70CST Registered User Join Date: May 2012 Location: Nor Cal, CA Posts: 17	Re: Motor mounting question Thank you! I’d like to keep the big block brackets so I can put the original big block back in one day. But thank you for the reply.

10-16-2019, 09:12 PM	#4
Andy4639 Old member Join Date: Jan 2002 Location: Liberty, & Garden City S.C. , U.S. Posts: 19,936	Re: Motor mounting question I just did this but the other direction. I'm going from a six to a V-8. I moved it and drilled new bottom holes. __________________ 1971 LWB Custom, 6.0LS & 4L80E, Speedhut.com GPS speedometer & gauges with A/C. 20" Boss 338's Grey wheels 4 wheel disc brakes. My Driver Seeing the USA in a 71 Upstate SC GM Truck Club 2013,14 and 2016 Hot Rod Pour Tour http://upstategmtrucks.com/ Get out and drive the truck this summer and have some fun! It sucks not being able to hear! LWB trucks rule, if you don't think so measure your SWB! After talking to tech support at Air Lift I have found out that the kit I need is 60811. Per the measurements I gave them. Ride height of truck inside spring and inside diameter of springs.

10-16-2019, 10:47 PM	#6
randy500 Account Suspended Join Date: Jul 2016 Location: Tacoma, WA Posts: 6,873	Re: Motor mounting question No need to move the brackets back, the rear position is 6 cyl only. Besides if you did you would need a shorter driveshaft. I believe the big block brackrts sit the engine up and forward a little...its not much.

10-16-2019, 11:57 PM	#7
kwmech Senior Member Join Date: Mar 2003 Location: Colfax-California Posts: 8,387	Re: Motor mounting question Just bolt the small block down on the big block stands with the big block cushions. No need to move anything. Center line from the mounts to the back of the block is the same at 16''



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