Putting miles on 67, 402bbc VS 67 V6 305E

[geezer#99]

Here’s a mileage kicker for you!
Bought a 70 chevelle ss454 back in 1978. LS6, m22 and 3.08 gear. Previous owner didn’t like the solid lifter cam so he had a stock bb cam installed. Same basic cam as in your 402.
Highway driving at 65 mph it would get 22 mpg. That’s a Canuck gallon. Same as 18 mpg in US gallons. While it sipped fuel it was a real dawg to drive. Ran out of breath at 4500 rpm.
Drove it like that over the winter. In the spring swapped the cam to a LS6 spec but it was a hydraulic cam.
Took care of that gas sipping dawg. Dropped it back to 15 mpg in Canuck gallons. Awesome power difference. Would light em up all the way thru 3rd even with the 3.08 gear.
And now back to your regular programming.

[67km1590]

Could you call me, five one three, five one eight, three five zero one.

[1967GMCC20]

Originally Posted by geezer#99

Here’s a mileage kicker for you!
Bought a 70 chevelle ss454 back in 1978. LS6, m22 and 3.08 gear. Previous owner didn’t like the solid lifter cam so he had a stock bb cam installed. Same basic cam as in your 402.
Highway driving at 65 mph it would get 22 mpg. That’s a Canuck gallon. Same as 18 mpg in US gallons. While it sipped fuel it was a real dawg to drive. Ran out of breath at 4500 rpm.
Drove it like that over the winter. In the spring swapped the cam to a LS6 spec but it was a hydraulic cam.
Took care of that gas sipping dawg. Dropped it back to 15 mpg in Canuck gallons. Awesome power difference. Would light em up all the way thru 3rd even with the 3.08 gear.
And now back to your regular programming.

Very cool story. 3.08 gears would favor stock low speed, high torque cam. With that gear, you can win "farthest distance awards"... my truck runs great, but needs OD or lower gears. I do like going up hills in drive with 4.10s.

[Bob B.]

Originally Posted by factorystock

When GM started offering the 396-402 in 3/4 tons, a 3.54 Dana became standard equipment, but, if you have the wallet......................

Biggest problem with the V-6 in pickups was GMC usually geared them too low.

[Ironangel]

Originally Posted by RustyPile

Got a 454 in my '71.. It's a disease I tell you. The first symptom is you go around with a smile on your face. Also makes you forget about gas mileage..

No Lie My Brutha! I've always said "if your worried about gas mileage your drivin the wrong truck..."

[jimijam00]

Originally Posted by 67km1590

Could you call me, five one three, five one eight, three five zero one.

I think I saw that phone number on a bathroom wall at Playpen Gentleman's Club. The name above the number was Trisha.

[1967GMCC20]

My 67 has Patina, but when I open hood with BBC 402, people step back woooo. Is Big Block that big a deal in trucks?

[MJN]

Originally Posted by 1967GMCC20

So the rear X member on bell housing is same. Mine is all there. The engine Bell housings were SAE, so I suspect similar.

I chisled the rivits, not torched.

I have the dust shield from Bell housing. Got left behind when I sold engine.

Not to hijack but I have a GMC V6 to SM420 bellhousing. They're not SAE patterns, http://67-72chevytrucks.com/vboard/s...mc+bellhousing

[71CHEVYSHORTBED402]

My 402 just recently came back to life after a 7 yr. hibernation, SWB truck. It's a low mileage rebuild, I only installed new pumps, timing and such since. It runs better than it ever has, I couldn't be happier. It's not quite stock, the heads are 1967 GM HP 396, Delco HEI distributor and high RPM cam.

Differential is a low RPM under-achievement at 3.73:1, there's no burning tires in first gear. On shift it can chirp, that's it. But loves the highway, it just wants to fly. That's what I've always liked about it. No matter how steep a hill it gains speed under little acceleration, and without more.

[1967GMCC20]

Originally Posted by MJN

Not to hijack but I have a GMC V6 to SM420 bellhousing. They're not SAE patterns, http://67-72chevytrucks.com/vboard/s...mc+bellhousing

Well I got that from 6066. V6 site, they have volumes on the V6. Just checked. Bet it was the larger V6, Larger trucks with 5spd. https://www.smokstak.com/forum/threa...gmc-v6.145198/

I mis read that on the GMC site on design of the engine. V12, large HD truck V6.

Your trans, bolts to my bell housing, same as NP435G (the real 4spd).

[jimijam00]

Originally Posted by 71CHEVYSHORTBED402

My 402 just recently came back to life after a 7 yr. hibernation, SWB truck. It's a low mileage rebuild, I only installed new pumps, timing and such since. It runs better than it ever has, I couldn't be happier. It's not quite stock, the heads are 1967 GM HP 396, Delco HEI distributor and high RPM cam.

Differential is a low RPM under-achievement at 3.73:1, there's no burning tires in first gear. On shift it can chirp, that's it. But loves the highway, it just wants to fly. That's what I've always liked about it. No matter how steep a hill it gains speed under little acceleration, and without more.

A big block with 3.73s should be melting tires. What's wrong with yours?

[1967GMCC20]

I have not opened 4 barrel yet, still enjoying cruising.
Kinda wonder how it would run down qtr mile.


Hauled 10ft posts for grapevines today from Farm Store.

[71CHEVYSHORTBED402]

Originally Posted by jimijam00

A big block with 3.73s should be melting tires. What's wrong with yours?

Couldn't tell you. It's never burned off go, or very little.

[Steeveedee]

Weird. If I cob mine, even with the shell on it and a 3.56 axle, it'll lay rubber and chirp second. No wheelies like the farm truck, though.

[71CHEVYSHORTBED402]

Originally Posted by Steeveedee

Weird. If I cob mine, even with the shell on it and a 3.56 axle, it'll lay rubber and chirp second. No wheelies like the farm truck, though.

Right, and my block sports HP heads off a 67ish 396 SS.

Don't mind me, I don't know what I'm talking about. First off my kick down never worked. Second I had 8" wheels and 70s, so on and so forth, and I probably baby it too much. Everything works now, lots rebuilt, timing chain, trans., axle, carb. etc. I just changed the oil today and figured it's time to really test her out. It runs like a bat out of hell, I'm really surprised. Burns rubber all kinds of ways, but I still refuse to jump from a dead start Too many rocks.

[1967GMCC20]

BBC Keeps running good. Hooking up neutral safety on Lokar shifter today. Thought about that when was going to let someone take it for a spin.

It's amazing how smooth this engine 402bbc runs. Torque is definitely big block.

[1967GMCC20]

Next will be adding trailer brake controller so I can pull car hauler.

[68panelman]

Show us some pictures of this beast..

[71CHEVYSHORTBED402]

Originally Posted by 68panelman

Show us some pictures of this beast..

I'd like to hear it too

[1967GMCC20]

Have not figured out wonky photo upload process. If it takes more than 3 steps...forget about it.

[1967GMCC20]

Can see no pic attachment, what is this the Zuckerberg software?

[1967GMCC20]

Just ordered a vintage NOS Kelsey Hayes brake controller fir 67 GMC. Now I can have trailer brakes on the oldie.

[1967GMCC20]

Still have NP435G from truck.

[1967GMCC20]

Pics

[1967GMCC20]

Adding Kelsey Hayes brake controller for pulling trailer.