Bolt Pattern for Bell Housing...350 vs. 250? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

67Dad · 12-07-2010, 11:29 PM

Our straight six 250 has a cracked cylinder.

Possible replacement located is a 1993 4 bolt 350 SBC.

Does anyone know if the bell housing from engine to transmission would match with the old 250 or if adapters are available (tranny is Muncie SM420 4speed).

Length of drive shaft could be an issue, too, I suppose.

Thanks.

Mark

jablack · 12-07-2010, 11:30 PM

Same pattern, will bolt right up.

67Dad · 12-07-2010, 11:50 PM

Terrific. Many thanks for the quick reply! Mark

Jacfourteen · 12-08-2010, 02:40 AM

Drive shaft alterations aren't necessary, just drop the 350 in using your I6 towers and get a upper rad hose and fan shroud from a 4wd truck (they sat in the same location as the I6 too). It will sit back about 3" or 4" farther than the 2wd v8 mounting position, but it works just fine, that is how mine is set up. Anymore questions hit me up.

57larry · 12-08-2010, 08:15 PM

use the V8 mounts, the 6 cyl mounts has the HEI dist right next to the firewall and the fan too far from the radiator. Do it right, the factory way

raycow · 12-11-2010, 05:08 AM

If you use the front set of holes you will have to deal with the clutch linkage as well as the driveshaft. Use the 6 cyl holes and save yourself a bunch of work.

Ray

RCbowtie69 · 12-11-2010, 10:00 PM

I Love Chevy's, BB or SB or 6 cyl. the trans will fit, same bolt pattern,my truck was 6 cyl. now a V-8 cool,still setting were 6 was, from PO, keep on truckin'

brad_man_72 · 12-12-2010, 01:58 AM

you could even bolt up an ls based engine with a crank spacer. Put the 8 on the 6 stands it never hurts these old trucks to move the engine back a few inches. Makes for a better weight bias, that means it will turn better.

ATrain707 · 12-12-2010, 03:10 AM

im in the same position, i have a 250 in my 68 c10 1/2 ton long bed with a 4speed. whats the easy way of doing that will work?if i didnt use the 250 mouting holes i would have to drill new ones? and if i use the 6 cycl holes everything will bolt up ok? drive shaft, tranny, clutch? the 350 i bought can with the fly wheel and clutch will these work/bolt with my stock bell housing and with with my 4speed tranny? oh and will the stock straight 6 motor mounts in the trucks work? or should i buy v8 mounts, sorry for all the question

and thnx for the help

12-07-2010, 11:29 PM	#1
67Dad Registered User Join Date: Mar 2010 Location: houston texas Posts: 84	Bolt Pattern for Bell Housing...350 vs. 250? Our straight six 250 has a cracked cylinder. Possible replacement located is a 1993 4 bolt 350 SBC. Does anyone know if the bell housing from engine to transmission would match with the old 250 or if adapters are available (tranny is Muncie SM420 4speed). Length of drive shaft could be an issue, too, I suppose. Thanks. Mark __________________ Mark 57 Austin Healey 3000 (sold many moons ago, unfortunately) 67 C10 (in progress, son's) w/ 1993 350 SBC, '96 Vortec heads (custom polished ports), EPS Performer intake, Holley carb, cam, MSD ignition 93 C4 Corvette (mostly done, son's)

12-07-2010, 11:30 PM	#2
jablack Classic Chevy Recycler Join Date: Dec 2007 Location: Alabama Posts: 422	Re: Bolt Pattern for Bell Housing...350 vs. 250? Same pattern, will bolt right up. __________________ 2004 Chevrolet Trailblazer EXT 1970 Chevrolet C50 1979 Chevrolet C30 Need another 67 or 68 soon...

12-07-2010, 11:50 PM	#3
67Dad Registered User Join Date: Mar 2010 Location: houston texas Posts: 84	Re: Bolt Pattern for Bell Housing...350 vs. 250? Terrific. Many thanks for the quick reply! Mark __________________ Mark 57 Austin Healey 3000 (sold many moons ago, unfortunately) 67 C10 (in progress, son's) w/ 1993 350 SBC, '96 Vortec heads (custom polished ports), EPS Performer intake, Holley carb, cam, MSD ignition 93 C4 Corvette (mostly done, son's)

12-08-2010, 02:40 AM	#4
Jacfourteen Big Red - Now its a SWB! Join Date: Jun 2009 Location: Oroville, Ca Posts: 1,624	Re: Bolt Pattern for Bell Housing...350 vs. 250? Drive shaft alterations aren't necessary, just drop the 350 in using your I6 towers and get a upper rad hose and fan shroud from a 4wd truck (they sat in the same location as the I6 too). It will sit back about 3" or 4" farther than the 2wd v8 mounting position, but it works just fine, that is how mine is set up. Anymore questions hit me up. __________________ 68 3/4 ton (Project)-350 Small Block, .030 over, 10:1 comp, 3998993 heads, C3BX edelbrock intake, comp cams XE268, Holley 670 SA, long tube headers, dual flow 40's, E-fan, Alum rad, currently under the knife getting shortened and bagged build thread 41 3/4 ton (wife's)-flatbed, fully restored to original 01 Tahoe LT 4WD (my daily driver)-Magnaflow Muffler, Rollin on 22's 02 Ford Mustang Convertable (Wife's Car)-Flowmaster 50, Clear corners, Intake, sittin on 18's

12-08-2010, 08:15 PM	#5
57larry Registered User Join Date: Nov 2007 Location: Indianapolis Posts: 1,161	Re: Bolt Pattern for Bell Housing...350 vs. 250? use the V8 mounts, the 6 cyl mounts has the HEI dist right next to the firewall and the fan too far from the radiator. Do it right, the factory way

12-11-2010, 05:08 AM	#6
raycow Registered User Join Date: Mar 2003 Location: San Francisco, CA USA Posts: 2,454	Re: Bolt Pattern for Bell Housing...350 vs. 250? If you use the front set of holes you will have to deal with the clutch linkage as well as the driveshaft. Use the 6 cyl holes and save yourself a bunch of work. Ray __________________ Live more responsibly. Eat lower on the food chain. Eat vegetarians.

12-11-2010, 10:00 PM	#7
RCbowtie69 Registered User Join Date: Dec 2003 Location: Thomasville, NC Posts: 1,877	Re: Bolt Pattern for Bell Housing...350 vs. 250? I Love Chevy's, BB or SB or 6 cyl. the trans will fit, same bolt pattern,my truck was 6 cyl. now a V-8 cool,still setting were 6 was, from PO, keep on truckin'

12-12-2010, 01:58 AM	#8
brad_man_72 the boat guy Join Date: Jul 2007 Location: springfield mo Posts: 2,339	Re: Bolt Pattern for Bell Housing...350 vs. 250? you could even bolt up an ls based engine with a crank spacer. Put the 8 on the 6 stands it never hurts these old trucks to move the engine back a few inches. Makes for a better weight bias, that means it will turn better. __________________ 67, swb, fleet, tach, throttle, 5.3, 4l60e, 3.73's, fuel cell, 5 lug, p.d.b., 4-6 drop. great little truck 66, stevens drag/ski 18' silouette, 350, 2.02 doublehump heads. comp extreme marine 278 cam, vette 7 fin valve covers, old polished edelbrock intake, velvetdrive, casale v-drive, adj cavitation plate. 28, model a rpu project,

12-12-2010, 03:10 AM	#9
ATrain707 Registered User Join Date: Sep 2010 Location: ukiah CA Posts: 179	Re: Bolt Pattern for Bell Housing...350 vs. 250? im in the same position, i have a 250 in my 68 c10 1/2 ton long bed with a 4speed. whats the easy way of doing that will work?if i didnt use the 250 mouting holes i would have to drill new ones? and if i use the 6 cycl holes everything will bolt up ok? drive shaft, tranny, clutch? the 350 i bought can with the fly wheel and clutch will these work/bolt with my stock bell housing and with with my 4speed tranny? oh and will the stock straight 6 motor mounts in the trucks work? or should i buy v8 mounts, sorry for all the question and thnx for the help Last edited by ATrain707; 12-12-2010 at 03:22 AM.

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