67 c20 with 3speed granny and 6 cyl???

[Ed ke6bnl]

I just brought home another truck 1967 C20 with a 3speed and granny gearbox. and a 6 cyl. I want to put my 454 ci in it. will it bolt up where the 6 is now do they have a special bolt pattern for the six the F**d maker has differant bolt patterns 6 to 8cyl.. I guess I will need a flywheel instead of a flexplate not sure what else if it is a bolt up, engine mounts moved, bigger radiator, can't think of much else. thanks still a while to go want to take these part from my 80 gmc crew dually and get rid of the smog people. thanks Ed

['68OrangeSunshine]

If the shifter is on the column, you have a Saginaw transmission. If the shifter is on the floor --it's considered a 4-speed (even if a "granny -1 -2 -3" set-up). If that's the original tranny, it would be an SM420. If someone put in a later 4-speed, it could be an SM465. '67 was the last year for the 420 in US production.
Good news is the transmission bolt pattern is the same, be it L6, SBC V8 or BBC V8. Unlike the competition, GM was into versatility and interchangability.
Only ripple is the Saginaw bellhousing has too small an opening for the front flange of a 465. [Don't know about the 420's fit.] Otherwise the bellhousings are identical.
Anyway an SM420 or 465 behind a 454 should be no problem. You might have to upgrade the flywheel to 11" or 12" -- depending on what diameter is in there now. 250s came with 10" or (?)10.5" and 292s usually came with 11" flywheels. [Until '72 when it bumped up to 12"].
I'm not familiar with the Saginaw unit to say how well it would do behind a big block. It could be cool, or it could be a grenade.

[Ed ke6bnl]

Originally Posted by '68OrangeSunshine

If the shifter is on the column, you have a Saginaw transmission. If the shifter is on the floor --it's considered a 4-speed (even if a "granny -1 -2 -3" set-up). If that's the original tranny, it would be an SM420. If someone put in a later 4-speed, it could be an SM465. '67 was the last year for the 420 in US production.
Good news is the transmission bolt pattern is the same, be it L6, SBC V8 or BBC V8. Unlike the competition, GM was into versatility and interchangability.
Only ripple is the Saginaw bellhousing has too small an opening for the front flange of a 465. [Don't know about the 420's fit.] Otherwise the bellhousings are identical.
Anyway an SM420 or 465 behind a 454 should be no problem. You might have to upgrade the flywheel to 11" or 12" -- depending on what diameter is in their now. 250s came with 10" or (?)10.5" and 292s usually came with 11" flywheels. [Until '72 when it bumped up to 12"].
I'm not familiar with the Saginaw unit to say how well it would do behind a big block. It could be cool, or it could be a grenade.

OrangeSunshine, thanks for the detail explanation I will print it up a save it. The transmission is on the floor. So the news is good so far. I may comming back to you to find out exactly what motor is in there its a straight six and the guy said it was a 235 ci. but will have to find out for sure. got two other cars down and they take priority till I am freed up. Thanks for the input Ed ke6bnl

['68OrangeSunshine]

235 CI would be not stock for a '67. '62 was the last model-year for the 235/261 series. 230 (not usual for a truck), 250 (common) and 292 (heavy duty option) comprised the L22 family of L6s made from model year '63 thru the '80s [minus the 230]. The L22 series is distinguished from the earlier Chevy and GMC L6s by having 2 separate side (lifter) covers. The earlier engines had a long one-piece cover. Both types are on the passenger side. The way to tell a 292 from a 250 is by the height of the lifter cover -- 250s are 4" and 292s are 6" tall. 292 also has a stagger in the engine mounts. 250 mounts are symetrical. The fuel pump is forward of the motor mount on a 250 and aft of the mount on the 292. The 292 is a great truck engine, not real fast, but lots of low end torque. Torque is comparable to a 454 at low RPMs, 350 is not even close. You have to rev up a 350 to get power out of it.
You can get the dress numbers from the pad on the block, pass. side aft of the distributor and post on the www.inliners.org board to get the displacement, build date and factory of origin.
OBTW is there an airstrip at Agua Dulce, Calif? I used to ride shotgun with my buddy when he did touch and goes in a Cessna 150 into there. White-knuckled fun. Back when gas was cheap and these trucks were new.
3s&8s.

[Ed ke6bnl]

Originally Posted by '68OrangeSunshine

235 CI would be not stock for a '67. '62 was the last model-year for the 235/261 series. 230 (not usual for a truck), 250 (common) and 292 (heavy duty option) comprised the L22 family of L6s made from model year '63 thru the '80s [minus the 230]. The L22 series is distinguished from the earlier Chevy and GMC L6s by having 2 separate side (lifter) covers. The earlier engines had a long one-piece cover. Both types are on the passenger side. The way to tell a 292 from a 250 is by the height of the lifter cover -- 250s are 4" and 292s are 6" tall. 292 also has a stagger in the engine mounts. 250 mounts are symetrical. The fuel pump is forward of the motor mount on a 250 and aft of the mount on the 292. The 292 is a great truck engine, not real fast, but lots of low end torque. Torque is comparable to a 454 at low RPMs, 350 is not even close. You have to rev up a 350 to get power out of it.
You can get the dress numbers from the pad on the block, pass. side aft of the distributor and post on the www.inliners.org board to get the displacement, build date and factory of origin.
OBTW is there an airstrip at Agua Dulce, Calif? I used to ride shotgun with my buddy when he did touch and goes in a Cessna 150 into there. White-knuckled fun. Back when gas was cheap and these trucks were new.
3s&8s.

Thanks so much for the valuable information, I had driven an old econline for some 4 years and was some what familliar with the differant straight sixes but the chevy was a new one for me. I never thought of going to the inliners site for. For some reason I just associated it with my old ford. Chevy sure did things better even with the sixes with its compatability with other engines. I do prefer the chevy and put a 63 chevy corvette motor in my Ford F1. your right again we have a small air strip that is difficult to land and take off from in Agua Dulce, It is under a major reconstruction and remoderling. I was heavy in ham radio and would talk to people all over the USA and was surprised on how many people from all over were familiar with this tiny airport. Nice little community I have lived hear 20 years. I even got an email from the guy from classic rides I think a DIY show, on his experiences in Agua Dulce. Thanks for all your help, I still not sure how we will go with the truck I just got it and it needs a lot of body work no rust but kinda beat up, but want to strip my 80 gmc dually crew cap and make a good dependable tow vehicle for my rv trailer and a work truck, and rid myself of the Smog Cops. Thanks agian Ed ke6bnl

[Ed ke6bnl]

Originally Posted by '68OrangeSunshine

235 CI would be not stock for a '67. '62 was the last model-year for the 235/261 series. 230 (not usual for a truck), 250 (common) and 292 (heavy duty option) comprised the L22 family of L6s made from model year '63 thru the '80s [minus the 230]. The L22 series is distinguished from the earlier Chevy and GMC L6s by having 2 separate side (lifter) covers. The earlier engines had a long one-piece cover. Both types are on the passenger side. The way to tell a 292 from a 250 is by the height of the lifter cover -- 250s are 4" and 292s are 6" tall. 292 also has a stagger in the engine mounts. 250 mounts are symetrical. The fuel pump is forward of the motor mount on a 250 and aft of the mount on the 292. The 292 is a great truck engine, not real fast, but lots of low end torque. Torque is comparable to a 454 at low RPMs, 350 is not even close. You have to rev up a 350 to get power out of it.
You can get the dress numbers from the pad on the block, pass. side aft of the distributor and post on the www.inliners.org board to get the displacement, build date and factory of origin.
OBTW is there an airstrip at Agua Dulce, Calif? I used to ride shotgun with my buddy when he did touch and goes in a Cessna 150 into there. White-knuckled fun. Back when gas was cheap and these trucks were new.
3s&8s.

Well I got to working on it a little and it is a 250 from your information. set the valves they are little noisy I guess as are most solid lifters. set the timing and seems to run ok maybe need some carborator work. but it is purky, with the 4.50:1 gears and the granny it is like my boy 4x4 in low range. I was surprised to have 4.5 gears and a what seems like a full floating rear end and only be a 10 bolt rear end. Still up in the air what the future of the truck is. Thanks for all your help ED

[da-burb]

The gears will actually be 4.56's and that rear end is known as a Corporate or Eaton rear end and also coded as a HO52 (3/4 ton) or HO72 (1 ton). You don't have a lot of choice in gears in it. 4.10's and 3.90's(aftermarket). You might want to swap it with a 14 bolt and save yourself the future repair headaches. Although they are bullet proof, the parts are spendy and sometimes hard to find.

You will need a 454 flywheel should you go that way. 454's are externally balanced and part of the balancing is in the flywheel.

['68OrangeSunshine]

If I recall correctly, some Dana 60(?) rearends for 3/4 ton had 10 bolts on the carrier cover, but are not to be confused with the GM Corp 10-Bolt of S/10 fame.
Hydraulic lifters were stock. There are guys racing 250s, so you can get solid lifters for them, but I would not suspect that of a farm truck. L6s do sound clacky, especialy if sitting for a while.
250s are OK, I have no experience running them. Too bad. I was gonna make you an offer for it, if it was a 292