Engine swap choices 4x4 Hell - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Rednwhitec20 · 02-02-2016, 10:11 PM

Hello, I am in the process of rebuilding my 1971 k20 from the frame up. I am wanting to go fuel injected because it will be a daily driver. I am not too concerned on gas mileage but it can help. Right now I'm looking between a 4bt, 6.0 Ls, and maybe even and 8.1 ls. The 4bt will get great mileage but I'm not sure how much it would cost to lay down some decent numbers like 250-300 hp and 450-500 ft. Lbs. the 6.0 and 8.1 will get about the same mileage but the 8.1 is a monster and I will probably keep it stock for a while. I will be going with an nv4500 transmission no matter what the choice is unless I get a deal with a nice transmission included.

**special-K** · 02-03-2016, 08:13 AM

No swap is still a good option. 250-300 is easy with a 350. In 1970 the 350 was 250hp stock. Never experienced hell with that

Mike C · 02-03-2016, 09:09 AM

All of your suggestions are expensive FWIW. And big blocks into a 67-72 can be a hassle as well because of how far the motor sits back. The 4BT makes tons of torque but is heavy. And loud.

Dollar per dollar a 383 is the way to go if you are cheap like me. Plenty of support for GM TBI/TPI or even aftermarket injection.

I'd be looking at GM's 383HT and a Q-jet since it seems to hit all the targets and should be warranties as well.

El Dorado Jim · 02-03-2016, 05:10 PM

Quote:

Originally Posted by Mike C

All of your suggestions are expensive FWIW. And big blocks into a 67-72 can be a hassle as well because of how far the motor sits back. The 4BT makes tons of torque but is heavy. And loud.

Dollar per dollar a 383 is the way to go if you are cheap like me. Plenty of support for GM TBI/TPI or even aftermarket injection.

I'd be looking at GM's 383HT and a Q-jet since it seems to hit all the targets and should be warranties as well.

I second this!

**Dieselwrencher** · 02-03-2016, 05:25 PM

Quote:

Originally Posted by Rednwhitec20

Hello, I am in the process of rebuilding my 1971 k20 from the frame up. I am wanting to go fuel injected because it will be a daily driver. I am not too concerned on gas mileage but it can help. Right now I'm looking between a 4bt, 6.0 Ls, and maybe even and 8.1 ls. The 4bt will get great mileage but I'm not sure how much it would cost to lay down some decent numbers like 250-300 hp and 450-500 ft. Lbs. the 6.0 and 8.1 will get about the same mileage but the 8.1 is a monster and I will probably keep it stock for a while. I will be going with an nv4500 transmission no matter what the choice is unless I get a deal with a nice transmission included.

To get 250-300hp from a 4bt you will need to start with a P-pump engine. Those seem to be going for $2500 on up. 250-300hp is do-able but you will need injectors, upgraded turbo, gov springs, add a nice vibration dampner. So cheap won't be in that swap. The LS would be a cheaper swap for sure.

72MARIO · 02-03-2016, 06:52 PM

After alot of though I decided to go 6.0 LQ4. There cheap and run for a very long time.

02-02-2016, 10:11 PM	#1
Rednwhitec20 Registered User Join Date: Jun 2014 Location: Princeton Kansas Posts: 235	Engine swap choices 4x4 Hell Hello, I am in the process of rebuilding my 1971 k20 from the frame up. I am wanting to go fuel injected because it will be a daily driver. I am not too concerned on gas mileage but it can help. Right now I'm looking between a 4bt, 6.0 Ls, and maybe even and 8.1 ls. The 4bt will get great mileage but I'm not sure how much it would cost to lay down some decent numbers like 250-300 hp and 450-500 ft. Lbs. the 6.0 and 8.1 will get about the same mileage but the 8.1 is a monster and I will probably keep it stock for a while. I will be going with an nv4500 transmission no matter what the choice is unless I get a deal with a nice transmission included.

02-03-2016, 08:13 AM	#2
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Engine swap choices 4x4 Hell No swap is still a good option. 250-300 is easy with a 350. In 1970 the 350 was 250hp stock. Never experienced hell with that __________________ "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 ~

02-03-2016, 09:09 AM	#3
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,727	Re: Engine swap choices 4x4 Hell All of your suggestions are expensive FWIW. And big blocks into a 67-72 can be a hassle as well because of how far the motor sits back. The 4BT makes tons of torque but is heavy. And loud. Dollar per dollar a 383 is the way to go if you are cheap like me. Plenty of support for GM TBI/TPI or even aftermarket injection. I'd be looking at GM's 383HT and a Q-jet since it seems to hit all the targets and should be warranties as well. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

02-03-2016, 06:52 PM	#6
72MARIO Registered User Join Date: Nov 2000 Location: Huntsville Ontario Canada Posts: 4,051	Re: Engine swap choices 4x4 Hell After alot of though I decided to go 6.0 LQ4. There cheap and run for a very long time. __________________ 1968 Suburban numbers matching all original truck now equipped with 6.0/4L80 on Accuair http://67-72chevytrucks.com/vboard/s...d.php?t=625017 1967 C/20 6.0/4L80 Roofing Truck 1990 V2500 Suburban "Plow Truck" 2005 TAHOE DD

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