Putting miles on 67, 402bbc VS 67 V6 305E - The 1947 - Present Chevrolet & GMC Truck Message Board Network

1967GMCC20 · 05-05-2023, 08:48 PM

Amazed how much better this GMC drives after pulling 305E and upgrading to 402 BBC. conversion.

Drives like a car, smooth, V6 was unique, but seriously under powered.

305E V6 7.5mpg. 170hp

402 bbc 12mpg. 310hp

jimijam00 · 05-05-2023, 08:58 PM

What year is the 402? GM didn't punch out the 396 until 1970.

1967GMCC20 · 05-05-2023, 09:06 PM

I got the 402 from a 1970 SWB CST takeout.
All date codes are correct for vehicle it came from.

All I changed was intake to a Holley cast iron 1966 hi rise.

1967GMCC20 · 05-05-2023, 09:08 PM

Thinking next upgrade, is a gear vendor over drive. Then I can run freeway speeds..

factorystock · 05-06-2023, 10:19 AM

Quote:

Originally Posted by 1967GMCC20

Thinking next upgrade, is a gear vendor over drive. Then I can run freeway speeds..

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

**Bob B.** · 05-09-2023, 11:53 AM

Quote:

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.

**MikeB** · 05-06-2023, 12:24 PM

Quote:

Originally Posted by 1967GMCC20

Thinking next upgrade, is a gear vendor over drive. Then I can run freeway speeds..

What's the current axle ratio? A mild 402 with all that torque should work just fine with a 3.08 or even a 2.73, depending on tire height and desired highway speeds.

My 82 C10 had a mild 355/TH350 with a 2.73 and 29.5" tall tires. Cruising at 70mph was ez-peezy, but it would spin the tires in first gear.

Just trying to save you from OD expense and hassles, although the GV should be less of a PITA than a 700R4. And it will never break!

**Palf70Step** · 05-05-2023, 09:20 PM

Gladyou like it. Theb6 can rip a building out of its foundation, but definitely lacks hiway guts. The OD will definitely help calm the BBCon the hiwY also

1967GMCC20 · 05-05-2023, 09:26 PM

Yep, V6. Had good low end lugging torque, but also lacked RPM. It went to a good home, guy restoring K20 4x4 GMC V6 truck.

This 402.. goes up steep hills in Drive that put my V6 in 1st.

I only need OD and then this is a true parts chaser.

I have the NP435G trans, and trans cross member and mounts, and engine mounts for V6 if someone needs them.

**Ironangel** · 05-05-2023, 11:18 PM

Quote:

Originally Posted by 1967GMCC20

Amazed how much better this GMC drives after pulling 305E and upgrading to 402 BBC. conversion.

Drives like a car, smooth, V6 was unique, but seriously under powered.

305E V6 7.5mpg. 170hp

402 bbc 12mpg. 310hp

Your very likely ruined for life! Once you feel the torque and the pony's them BBC's make, they own you! "Jus sayin"

RustyPile · 05-06-2023, 01:11 AM

Quote:

Originally Posted by Ironangel

Your very likely ruined for life! Once you feel the torque and the pony's them BBC's make, they own you! "Jus sayin"

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..

1967GMCC20 · 05-08-2023, 06:19 PM

Quote:

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..

Had a 78 suburban with 454, ran good, ended putting eng and trans TH400 in a 78 Silverado that was originally a diesel. It had 2.73 gears. Was perfect for Texas freeways and FM roads.

**Ironangel** · 05-09-2023, 07:30 PM

Quote:

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..."

1967GMCC20 · 05-06-2023, 01:49 PM

Ran another 100mi + today, with 10gal of premium thru the big block.

Truck has 4.10 gear Dana 60.

**Palf70Step** · 05-06-2023, 04:11 PM

So 8 to 10 MPG whether your driving easy, towing or whatever then.

1967GMCC20 · 05-07-2023, 08:27 AM

Quote:

Originally Posted by Palf70Step

So 8 to 10 MPG whether your driving easy, towing or whatever then.

12mpg rolling empty road trip, 55mph is. 402bbc

V6 7.5mpg uphill, down hill, hauling water.. it just liked fuel. But since designed in late 50s, looks like ports from a 348...anchor, neither designed for fuel economy, but fuel was cheap. Massively heavy built, designed for durability. My old V6 is going in a 67 4x4 restoration, his block was cracked. Win-Win

1967GMCC20 · 05-07-2023, 08:23 AM

Front sway bar is going to be next.... lot of nice winding roads to be seen.

**67km1590** · 05-08-2023, 02:53 PM

If your friend would happen to know of a extra set of V6 4X4 engine perches I'm in bad need of a set for my restoration. My truck had been converted to a sbc at one time but it did have the original V6 with it. Thanks for any help.

1967GMCC20 · 05-08-2023, 04:31 PM

Are the front mounts the same? Bell housing on mine was 4spd,
If yours is a stick, it might be the same.

1967GMCC20 · 05-08-2023, 04:32 PM

Quote:

Originally Posted by 67km1590

If your friend would happen to know of a extra set of V6 4X4 engine perches I'm in bad need of a set for my restoration. My truck had been converted to a sbc at one time but it did have the original V6 with it. Thanks for any help.

You pay shipping, you can have them.

1967GMCC20 · 05-08-2023, 04:33 PM

Where in ohio? Pick them up, you can have three mounts, brackets, x member.

**67km1590** · 05-08-2023, 04:48 PM

I'm in Batavia, mine is a 4sp. Could you send me pictures, if they're right I'll be on the way. Thanks

1967GMCC20 · 05-08-2023, 05:41 PM

Bet it's same, not too many ways to mount that V6. Heading down to barn.

**67km1590** · 05-08-2023, 06:00 PM

I may not be able to get back to you until tomorrow.

1967GMCC20 · 05-08-2023, 06:04 PM

No problem, bet there is only one set of mounts for V6, big engine tight fit. I have eng mounts and frame mounts. And crossmember for bell housing to frame with mounts.

My 67 is here to look at frame hole locations.

05-05-2023, 08:48 PM	#1
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 224	Putting miles on 67, 402bbc VS 67 V6 305E Amazed how much better this GMC drives after pulling 305E and upgrading to 402 BBC. conversion. Drives like a car, smooth, V6 was unique, but seriously under powered. 305E V6 7.5mpg. 170hp 402 bbc 12mpg. 310hp

05-05-2023, 08:58 PM	#2
jimijam00 Registered User Join Date: Apr 2009 Location: PNW Posts: 553	Re: Putting miles on 67, 402bbc VS 67 V6 305E What year is the 402? GM didn't punch out the 396 until 1970.

05-05-2023, 09:06 PM	#3
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 224	Re: Putting miles on 67, 402bbc VS 67 V6 305E I got the 402 from a 1970 SWB CST takeout. All date codes are correct for vehicle it came from. All I changed was intake to a Holley cast iron 1966 hi rise.

05-05-2023, 09:08 PM	#4
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 224	Re: Putting miles on 67, 402bbc VS 67 V6 305E Thinking next upgrade, is a gear vendor over drive. Then I can run freeway speeds..

05-05-2023, 09:20 PM	#8
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,061	Re: Putting miles on 67, 402bbc VS 67 V6 305E Gladyou like it. Theb6 can rip a building out of its foundation, but definitely lacks hiway guts. The OD will definitely help calm the BBCon the hiwY also __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

05-05-2023, 09:26 PM	#9
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 224	Re: Putting miles on 67, 402bbc VS 67 V6 305E Yep, V6. Had good low end lugging torque, but also lacked RPM. It went to a good home, guy restoring K20 4x4 GMC V6 truck. This 402.. goes up steep hills in Drive that put my V6 in 1st. I only need OD and then this is a true parts chaser. I have the NP435G trans, and trans cross member and mounts, and engine mounts for V6 if someone needs them.

05-06-2023, 01:49 PM	#14
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 224	Re: Putting miles on 67, 402bbc VS 67 V6 305E Ran another 100mi + today, with 10gal of premium thru the big block. Truck has 4.10 gear Dana 60.

05-06-2023, 04:11 PM	#15
Palf70Step State of Confusion! Join Date: Jul 2002 Location: Gulfport, MS USA Posts: 47,061	Re: Putting miles on 67, 402bbc VS 67 V6 305E So 8 to 10 MPG whether your driving easy, towing or whatever then. __________________ Bill 1970 Chevy Custom/10 LWB Fleetside 2010 Toyota Tacoma PreRunner SR5 Double Cab - DD Member of Louisiana Classic Truck Club (LCTC) Bill's Gallery Life isn't tied with a bow, but it's still a gift. Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God!

05-07-2023, 08:23 AM	#17
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 224	Re: Putting miles on 67, 402bbc VS 67 V6 305E Front sway bar is going to be next.... lot of nice winding roads to be seen.

05-08-2023, 02:53 PM	#18
67km1590 Junior Member Join Date: Feb 2022 Location: Ohio Posts: 77	Re: Putting miles on 67, 402bbc VS 67 V6 305E If your friend would happen to know of a extra set of V6 4X4 engine perches I'm in bad need of a set for my restoration. My truck had been converted to a sbc at one time but it did have the original V6 with it. Thanks for any help.

05-08-2023, 04:31 PM	#19
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 224	Re: Putting miles on 67, 402bbc VS 67 V6 305E Are the front mounts the same? Bell housing on mine was 4spd, If yours is a stick, it might be the same.

05-08-2023, 04:33 PM	#21
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 224	Re: Putting miles on 67, 402bbc VS 67 V6 305E Where in ohio? Pick them up, you can have three mounts, brackets, x member.

05-08-2023, 04:48 PM	#22
67km1590 Junior Member Join Date: Feb 2022 Location: Ohio Posts: 77	Re: Putting miles on 67, 402bbc VS 67 V6 305E I'm in Batavia, mine is a 4sp. Could you send me pictures, if they're right I'll be on the way. Thanks

05-08-2023, 05:41 PM	#23
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 224	Re: Putting miles on 67, 402bbc VS 67 V6 305E Bet it's same, not too many ways to mount that V6. Heading down to barn. Last edited by 1967GMCC20; 05-08-2023 at 06:10 PM. Reason: Typo

05-08-2023, 06:00 PM	#24
67km1590 Junior Member Join Date: Feb 2022 Location: Ohio Posts: 77	Re: Putting miles on 67, 402bbc VS 67 V6 305E I may not be able to get back to you until tomorrow.



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05-08-2023, 06:04 PM	#25
1967GMCC20 Registered User Join Date: Apr 2022 Location: Medina, Ohio Posts: 224	Re: Putting miles on 67, 402bbc VS 67 V6 305E No problem, bet there is only one set of mounts for V6, big engine tight fit. I have eng mounts and frame mounts. And crossmember for bell housing to frame with mounts. My 67 is here to look at frame hole locations.

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