350 to I-6, Is it possible? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

TP from Cntl PA · 12-08-2003, 08:19 PM

I got a 350 in my '71 C-20 and I am getting really sick of it...........Has no guts(IMO) and is hard on fuel. We use it on the farm and I really need more low end torque. I have looked at building up another 350, but I am tired of working on V-8's

(Been wrenching on a Cummins "Triple Trouble, 555 for the entire summer!)...................I got a 250 six to bolt in, along with a granny 4spd.........Would this work? I don't want to hack anything up since I would put the 350/ 3spd back in when I restore it..................I'd really like to put a 4-71 Detroit in it, but I haven't found one

I know I am crazy................About Sixes!

"6 in a row makes it go!"

BLACK AND BLUE 67-72 · 12-08-2003, 08:24 PM

Yep, it can be done, you'll have to have the I6 mounts and support for the trans.

TP from Cntl PA · 12-08-2003, 08:26 PM

How much will I have to hack up.......Will the 6 mounts bolt right in? I am not worried about the tranny mount..........

SCOTI · 12-08-2003, 08:30 PM

6's are cool. But, to be perfectly honest the mpg's of my 250/3spd & 3.73's w/28" tall rear tires isn't any better than a 'camino I used to own. It had a 350 w/ported heads, .465/.480 crane cam, performer intake & 650 holley, & a 2.73 open rear end w/26" rear tires.

The 'camino was much more fun yet both avg'd 12-13 mpg city/hwy combined. I do like the fact that w/the 6 you can idle along smoothly @ extremely low speeds in gear & that's something V8's w/manual trannys just don't like to do.

BLACK AND BLUE 67-72 · 12-08-2003, 08:43 PM

Well if you had the mounts, trans., driveshaft, linkages, etc. it should bolt in with little or no modifications. There are already holes for the mounts in the crossmember and frame.

TP from Cntl PA · 12-08-2003, 08:58 PM

Did any of you ever try a 250/5spd? Will any GM 5spds bolt up to the 250? I really like to have a 5 spd!

SCOTI · 12-08-2003, 09:17 PM

If they will bolt up to a small block, they'll bolt up to a 250.

Longhorn Man · 12-09-2003, 01:46 AM

There was at least one guy on here who installed a T-5 out of a 3rd gen camarow into an inline powered truck.

Baradium · 12-09-2003, 01:49 AM

Quote:

Originally posted by SCOTI
6's are cool. But, to be perfectly honest the mpg's of my 250/3spd & 3.73's w/28" tall rear tires isn't any better than a 'camino I used to own. It had a 350 w/ported heads, .465/.480 crane cam, performer intake & 650 holley, & a 2.73 open rear end w/26" rear tires.

The 'camino was much more fun yet both avg'd 12-13 mpg city/hwy combined. I do like the fact that w/the 6 you can idle along smoothly @ extremely low speeds in gear & that's something V8's w/manual trannys just don't like to do.

That doesn't sound right IMO

I used to know someone who used to have a '70 pickup with a 250/3spd combo with 3.73s and 28" tires and he easily got 15mpg out of that truck and he was not easy on it by any means. I want to say his normal was around 16mpg.

This was a long bed 1/2 ton with the hd suspension.

Longhorn Man · 12-09-2003, 02:08 AM

theres some one on here with a small block basicly stock burb that gets way better than the 16 MPG that so amny of us try to get.
Seems most of the inline guys say that 10 is about right.

jku72 · 12-09-2003, 02:18 AM

Keep the mouse. Instead of engine swapping, try transmission swapping. For the best of all worlds, find an NV4500, offered in 93 and newer chevy and Dodge trucks. Its got a granny low 5.61:1, and a 27% overdrive.
I dont have one yet, but I want one bad. With my current 350, I'm getting 15-16 locally, and 18-19 on the highway.

12-08-2003, 08:19 PM	#1
TP from Cntl PA Registered User Join Date: Apr 2003 Location: Central PA....In the Berg of Nisbet Posts: 790	350 to I-6, Is it possible? I got a 350 in my '71 C-20 and I am getting really sick of it...........Has no guts(IMO) and is hard on fuel. We use it on the farm and I really need more low end torque. I have looked at building up another 350, but I am tired of working on V-8's (Been wrenching on a Cummins "Triple Trouble, 555 for the entire summer!)...................I got a 250 six to bolt in, along with a granny 4spd.........Would this work? I don't want to hack anything up since I would put the 350/ 3spd back in when I restore it..................I'd really like to put a 4-71 Detroit in it, but I haven't found one I know I am crazy................About Sixes! "6 in a row makes it go!" __________________ '72 K-20 EFI'ed 250 Inline/4spd stake body, Farm Truck '71 C-20 Cummins Diesel Powered, In storage thanks to $5.00 diesel! '69 3500 GMC 305V-6/4spd, Still under reconstruction.......... Inlines Rule! 6 soldiers standing is better than 8 laying down!!!!!!!!

12-08-2003, 08:24 PM	#2
BLACK AND BLUE 67-72 Firefighter Join Date: Feb 2001 Location: Yellville, Ar, USA Posts: 1,943	Yep, it can be done, you'll have to have the I6 mounts and support for the trans. __________________ '72 Chevy SWB 350 Auto '67 GMC LWB 350 4 speed '70 Chevy 4x4 Stepside 350 Auto Yellville, Ar. USA

12-08-2003, 08:26 PM	#3
TP from Cntl PA Registered User Join Date: Apr 2003 Location: Central PA....In the Berg of Nisbet Posts: 790	How much will I have to hack up.......Will the 6 mounts bolt right in? I am not worried about the tranny mount.......... __________________ '72 K-20 EFI'ed 250 Inline/4spd stake body, Farm Truck '71 C-20 Cummins Diesel Powered, In storage thanks to $5.00 diesel! '69 3500 GMC 305V-6/4spd, Still under reconstruction.......... Inlines Rule! 6 soldiers standing is better than 8 laying down!!!!!!!!

12-08-2003, 08:30 PM	#4
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,071	6's are cool. But, to be perfectly honest the mpg's of my 250/3spd & 3.73's w/28" tall rear tires isn't any better than a 'camino I used to own. It had a 350 w/ported heads, .465/.480 crane cam, performer intake & 650 holley, & a 2.73 open rear end w/26" rear tires. The 'camino was much more fun yet both avg'd 12-13 mpg city/hwy combined. I do like the fact that w/the 6 you can idle along smoothly @ extremely low speeds in gear & that's something V8's w/manual trannys just don't like to do. __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

12-08-2003, 08:43 PM	#5
BLACK AND BLUE 67-72 Firefighter Join Date: Feb 2001 Location: Yellville, Ar, USA Posts: 1,943	Well if you had the mounts, trans., driveshaft, linkages, etc. it should bolt in with little or no modifications. There are already holes for the mounts in the crossmember and frame. __________________ '72 Chevy SWB 350 Auto '67 GMC LWB 350 4 speed '70 Chevy 4x4 Stepside 350 Auto Yellville, Ar. USA

12-08-2003, 08:58 PM	#6
TP from Cntl PA Registered User Join Date: Apr 2003 Location: Central PA....In the Berg of Nisbet Posts: 790	Did any of you ever try a 250/5spd? Will any GM 5spds bolt up to the 250? I really like to have a 5 spd! __________________ '72 K-20 EFI'ed 250 Inline/4spd stake body, Farm Truck '71 C-20 Cummins Diesel Powered, In storage thanks to $5.00 diesel! '69 3500 GMC 305V-6/4spd, Still under reconstruction.......... Inlines Rule! 6 soldiers standing is better than 8 laying down!!!!!!!!

12-08-2003, 09:17 PM	#7
SCOTI Registered User Join Date: Apr 2001 Location: DALLAS,TX Posts: 22,071	If they will bolt up to a small block, they'll bolt up to a 250. __________________ 67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... *Cubic inches is like Indiana Jones with a cheap pistol.*

12-09-2003, 01:46 AM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	There was at least one guy on here who installed a T-5 out of a 3rd gen camarow into an inline powered truck.

12-09-2003, 02:08 AM	#10
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	theres some one on here with a small block basicly stock burb that gets way better than the 16 MPG that so amny of us try to get. Seems most of the inline guys say that 10 is about right.

12-09-2003, 02:18 AM	#11
jku72 Registered User Join Date: Jan 2002 Location: cornville, maine Posts: 659	Keep the mouse. Instead of engine swapping, try transmission swapping. For the best of all worlds, find an NV4500, offered in 93 and newer chevy and Dodge trucks. Its got a granny low 5.61:1, and a 27% overdrive. I dont have one yet, but I want one bad. With my current 350, I'm getting 15-16 locally, and 18-19 on the highway. __________________ jku Cornville, Maine 68 C10 burb 42 Willys MB 46 Dodge WF-32 1.5 ton 53 & 56 Olds' 60 Cadillac 22 Dodge Brothers



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