70 GMC 4spd 307 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cam · 05-25-2004, 09:56 AM

Good Morning, Can anyone tell me anything about the 307 V8 / 2 barrel carb, 4spd set up? I found a 70 gmc, LB, 125,000 miles, (rocker, cab corner, floorpan rust) with very minimal options, I believe it has a posi rear end and that's about it, doesn't even have a radio. The person that owns it wants $300, (and yes I'm going to buy it) says it needs a new steering box (he has one to install) and a heater core (he also has one of these to install). he said that it starts without fault but needs the valve seals replaced since it blows blue smoke when it starts up. I know the 307 is the same block as the 350 but really don't know anything else about it combined with a 2 barrel carb. Anyone had experience with one of these pickups? Also, how difficult is it to take the power brakes and power steering off of a 72 chev and make a swap?

Thanks again,
Scott

**CPNE** · 05-25-2004, 10:07 AM

All brackets and manifolds will swap off a 350 onto a 307. The PS and PB booster is a direct swap too. The 307 came standard with a 2 bbl rochester carb. If you go the 4bbl route with it be aware the gas lines are 5/16th, not the 3/8 line used on 4bbl smallblocks. The 307 is somewhat maligned, but is a good general purpose engine that will get you from point A to point B. Coupled with the 4 speed, you should have no problems hauling or towing loads. If you wish to upgrade to a bigger CU smallblock, it's a direct bolt in as the 307 shares the same outside dimensions as the 327, 350, and 400 small blocks.

JimKshortstep4x4 · 05-25-2004, 11:01 AM

We have a couple of trucks with the 307 engines in them and are very happy with them. One is in a longbed and I just got back from a 1600 mile trip with it. Performance is decent, (not like a 350) and the gas mileage is decent, (15-16 mpg). The other is a short fleetside and it is noticeably faster with the lighter truck. Gas mileage does not seem to change if the truck is loaded or not.

Our plan is to run the 307's until they die, (which may be awhile) and then replace them with 350's. 350's are cheaper to rebuild so we don't rebuild 307's.

Both the trucks are used for drivers.

Jim

05-25-2004, 09:56 AM	#1
cam Registered User Join Date: May 2002 Location: Helena, MT, USA Posts: 64	70 GMC 4spd 307 Good Morning, Can anyone tell me anything about the 307 V8 / 2 barrel carb, 4spd set up? I found a 70 gmc, LB, 125,000 miles, (rocker, cab corner, floorpan rust) with very minimal options, I believe it has a posi rear end and that's about it, doesn't even have a radio. The person that owns it wants $300, (and yes I'm going to buy it) says it needs a new steering box (he has one to install) and a heater core (he also has one of these to install). he said that it starts without fault but needs the valve seals replaced since it blows blue smoke when it starts up. I know the 307 is the same block as the 350 but really don't know anything else about it combined with a 2 barrel carb. Anyone had experience with one of these pickups? Also, how difficult is it to take the power brakes and power steering off of a 72 chev and make a swap? Thanks again, Scott __________________ 1970 GMC 1/2 ton 307 4spd 1970 dorF dump runner

05-25-2004, 10:07 AM	#2
CPNE Resident Curmudgeon Join Date: Dec 1999 Location: NH Posts: 6,664	All brackets and manifolds will swap off a 350 onto a 307. The PS and PB booster is a direct swap too. The 307 came standard with a 2 bbl rochester carb. If you go the 4bbl route with it be aware the gas lines are 5/16th, not the 3/8 line used on 4bbl smallblocks. The 307 is somewhat maligned, but is a good general purpose engine that will get you from point A to point B. Coupled with the 4 speed, you should have no problems hauling or towing loads. If you wish to upgrade to a bigger CU smallblock, it's a direct bolt in as the 307 shares the same outside dimensions as the 327, 350, and 400 small blocks. __________________ Currently on or near the homestead: 67 Chevy SWB 2WD stepside 350/3 on tree (Pat's) 67 GMC SWB 2WD Fleet 402/auto (Brian's under construction) 67 Chevy 3/4 ton 2WD 402/auto (Business Hauler) 67 Chevy 1 ton dually 2WD 396/4 speed (Former business hauler, Needs TLC) 68 Chevy 1/2 ton Suburban 2WD 250 six/3 on tree (Brian's Needs TLC) 70 Chevy 3/4 ton 4WD 350/4 speed (Pat's - Disguised as a 68 GMC) 71 Chevy SWB stepside (Crushed by tree - parts donor) 72 Chevy 3/4 ton 4WD (Parts donor) 72 Chevy 3/4 ton 4WD Suburban (Parts Donor) 72 GMC 3/4 ton 4WD 292 six/4 speed (Mine - Disguised as a 67 GMC) 81 GMC 4WD Dually Dump Body 350/4 speed (Business Hauler) 82 Camaro Z/28 355/Super T-10 (Pat's toy) 93 Caprice 9C1 (Brian's Cop Car) 02 Toyota Camry (Reliable but a souless steel and plastic hulk) 2011 2SS RS Camaro M6 Factory Hurst Shifter Maybe I need to sell some of this crap Yet another Bozo with a sawz-all

05-25-2004, 11:01 AM	#3
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	We have a couple of trucks with the 307 engines in them and are very happy with them. One is in a longbed and I just got back from a 1600 mile trip with it. Performance is decent, (not like a 350) and the gas mileage is decent, (15-16 mpg). The other is a short fleetside and it is noticeably faster with the lighter truck. Gas mileage does not seem to change if the truck is loaded or not. Our plan is to run the 307's until they die, (which may be awhile) and then replace them with 350's. 350's are cheaper to rebuild so we don't rebuild 307's. Both the trucks are used for drivers. Jim



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