installing a big block into a 67????? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**John Fabris** · 06-11-2007, 07:02 PM

Hi Gang,

Is there anyone here that has a true 67 1/2 truck that they have installed a big block into?

I want to find out a few things before I start working on my new 67 of which I have a 402/T400 combo that I want to install in it.

For example, what mods did you have to make for this to work? I know that the width of the top of the frame where the motor mounts go, needs to be trimmed back as the 72 bb mounts I have do not line up. Also, does the T400 fit under the cab that has a low hump or do I need to cut that out for a high hump?

Also any other tips?

67cst · 06-11-2007, 07:33 PM

all i can help with is the second part of your question, i have a low hump cab and the th400 clears the hump, its real close though because i have a lokar floor shifter and the bracket sits on top of the trans but with colum shift its not an issue whatsoever

Bob Moore · 06-11-2007, 08:56 PM

John - I can comment on the motor mount question. Go to the junkyard and trace the top rail of any 68 to 72 to get a pattern for the cut out. You will see that it is not very much that needs to be cut. I used 72 mounts and stock exhaust manifolds. The area of the frame where the manifolds pass gets tight without the cutout.

As I said above I used the 72 mounts, 454 with long waterpump and T-400. I did not know about the LWP vs SWP at that time. This time I am using the correct SWP and correct brackets. Only result of the LWP is very slight clearance between the fan and radiator.

I slid the automatic crossmember back to fit but only 3 of the 4 bolts on each side would fit. I did not lift the cab or redrill the frame. I have driven it since 93 with only those 3 bolts per side. IIR the ones that don't fit are the on the top. A 90 degree drill might fit but I did not have one. This time I will be able to drill for all 4.

The steering box was spaced about 1/8th inch using hardened washers and has not caused a problem.

Hope this helps - Bob

**John Fabris** · 06-11-2007, 11:08 PM

thanks guys... I did stop by my buddy's shop to look at a 72 short fleet that he is repainting, and I noticed the difference in the frame, so I do need to go back a make a template.

Cool to know the low cab will work with the 402. Less work for me!!!

Thanks again!

**special-K** · 06-12-2007, 06:51 AM

I hear it`s so close that it matters about the condition of the body mounts.I may be using a 454 in my`67 GMC project/low hump.

**John Fabris** · 06-12-2007, 10:31 AM

Ya, I ordered a new mount kit and will be installing that first along with rebuilding the door hinges before I start installing the big block. My plan is to build this truck as it is, get it running, then start customizing it, then I will blow it apart and paint it....

70rs/ss · 06-12-2007, 01:55 PM

They go together without much trouble. If you use stock manifolds you will have less issues. Headers get interesting. I actually mounted the motor, and loosely bolted the headers to mark the frame and two little spots were tight, dropped the header, ground it down and put it back together. I didn't want to cut the whole top rail so I opted for the less invasive approach.

06-11-2007, 07:02 PM	#1
John Fabris TOTY 2006 Join Date: Dec 1999 Location: Magalia CA USA Posts: 2,270	installing a big block into a 67????? Hi Gang, Is there anyone here that has a true 67 1/2 truck that they have installed a big block into? I want to find out a few things before I start working on my new 67 of which I have a 402/T400 combo that I want to install in it. For example, what mods did you have to make for this to work? I know that the width of the top of the frame where the motor mounts go, needs to be trimmed back as the 72 bb mounts I have do not line up. Also, does the T400 fit under the cab that has a low hump or do I need to cut that out for a high hump? Also any other tips? __________________ John Fabris 67 C10 SWB

06-11-2007, 07:33 PM	#2
67cst i love summertime Join Date: Jul 2002 Location: Kelowna BC Posts: 4,303	Re: installing a big block into a 67????? all i can help with is the second part of your question, i have a low hump cab and the th400 clears the hump, its real close though because i have a lokar floor shifter and the bracket sits on top of the trans but with colum shift its not an issue whatsoever __________________ 1967 shortbox stepside Chevy, 365 hp 327, th400. GLOVE BOX LIGHTS FORSALE, click link for info http://67-72chevytrucks.com/vboard/s...d.php?t=273724

06-11-2007, 08:56 PM	#3
Bob Moore Registered User Join Date: Feb 2004 Location: Tacoma WA Posts: 1,365	Re: installing a big block into a 67????? John - I can comment on the motor mount question. Go to the junkyard and trace the top rail of any 68 to 72 to get a pattern for the cut out. You will see that it is not very much that needs to be cut. I used 72 mounts and stock exhaust manifolds. The area of the frame where the manifolds pass gets tight without the cutout. As I said above I used the 72 mounts, 454 with long waterpump and T-400. I did not know about the LWP vs SWP at that time. This time I am using the correct SWP and correct brackets. Only result of the LWP is very slight clearance between the fan and radiator. I slid the automatic crossmember back to fit but only 3 of the 4 bolts on each side would fit. I did not lift the cab or redrill the frame. I have driven it since 93 with only those 3 bolts per side. IIR the ones that don't fit are the on the top. A 90 degree drill might fit but I did not have one. This time I will be able to drill for all 4. The steering box was spaced about 1/8th inch using hardened washers and has not caused a problem. Hope this helps - Bob __________________ 67 C-20 LWB, tilt, speed alert, vac, 454, T400 67 C-10 SWB, factory air with more to follow

06-11-2007, 11:08 PM	#4
John Fabris TOTY 2006 Join Date: Dec 1999 Location: Magalia CA USA Posts: 2,270	Re: installing a big block into a 67????? thanks guys... I did stop by my buddy's shop to look at a 72 short fleet that he is repainting, and I noticed the difference in the frame, so I do need to go back a make a template. Cool to know the low cab will work with the 402. Less work for me!!! Thanks again! __________________ John Fabris 67 C10 SWB

06-12-2007, 06:51 AM	#5
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,863	Re: installing a big block into a 67????? I hear it`s so close that it matters about the condition of the body mounts.I may be using a 454 in my`67 GMC project/low hump. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

06-12-2007, 10:31 AM	#6
John Fabris TOTY 2006 Join Date: Dec 1999 Location: Magalia CA USA Posts: 2,270	Re: installing a big block into a 67????? Ya, I ordered a new mount kit and will be installing that first along with rebuilding the door hinges before I start installing the big block. My plan is to build this truck as it is, get it running, then start customizing it, then I will blow it apart and paint it.... __________________ John Fabris 67 C10 SWB

06-12-2007, 01:55 PM	#7
70rs/ss Registered User Join Date: Dec 2004 Location: Northern AZ Posts: 7,271	Re: installing a big block into a 67????? They go together without much trouble. If you use stock manifolds you will have less issues. Headers get interesting. I actually mounted the motor, and loosely bolted the headers to mark the frame and two little spots were tight, dropped the header, ground it down and put it back together. I didn't want to cut the whole top rail so I opted for the less invasive approach.



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