Need V8 Swap Help - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Steve78LT · 06-24-2018, 05:28 PM

Swapping a SBC for the inline six. Swapped a bunch of motors in my day, but always V8 for V8, never an 8 for a 6. Here's where I'm at:

- Got the right V8 motor mounts and installed those, in the holes forward of the I6 holes on the frame (the only place they sould go).

- Kept the TH350 from the old motor, cleaned it up, changed the tranny mount.

- Moved the tranny crossmember forward to pick up the tailshaft. Or maybe I'd just reinstalled it in the wrong place the first time...

Here's what I need to know:

- The shifter linkage doesn't line up now. Looks like the bracket unbolts off the frame and moves forward (there are holes there already) but the rod that connects to the steering column doesn't look like it'll work. Its drilled for a cotter pin at the linkage, and tapered down at the other end to fit the connector at the column. Do I need a different rod, or am I missing something?

- The torque converter is tight against the flexplate, and won't turn to align the bolt holes. Probably should have bolted that together before installing the motor/tranny, but I figured that's be easier to do with the truck on the lift. When I put the TC on, I rotatated it until I heard 2 thunks, so I though it was seated. Dose a V8 use a different TC than a straight six, or did I just screw up the install?

- Will the driveshaft fit? I haven't checked this yet, but if the tranny moved forward because the V8 is shorter, will the driveshaft be too short? Or did V8s and 6s use the same driveshaft?

I figure somebody here has done the same swap, and lived through this already. I'd sure appreciate any advice I can get.

rjs53 · 06-24-2018, 05:48 PM

Just a question, did you make sure the torque convertor is in the transmission all the way? On the th350 you need to spin the convertor until it goes in a couple clicks, if not you'll brake the pump.

Steve78LT · 06-24-2018, 06:31 PM

Yup. Heard 2 thunks. Now, whether it slid forward in the process of installing the tranny on the motor, I can't say for sure. Before I pull the tranny out, I just wanted to make sure that both motors use the same converter.

**Getter-Done** · 06-24-2018, 07:19 PM

Welcome
First thing your torque convertor probably slipped out on you.
Second thing this link below may answer some of your other questions.
http://67-72chevytrucks.com/vboard/s...ds+on+a+350+v8

06-24-2018, 05:28 PM	#1
Steve78LT Registered User Join Date: Jun 2018 Location: Massachusetts Posts: 4	Need V8 Swap Help Swapping a SBC for the inline six. Swapped a bunch of motors in my day, but always V8 for V8, never an 8 for a 6. Here's where I'm at: - Got the right V8 motor mounts and installed those, in the holes forward of the I6 holes on the frame (the only place they sould go). - Kept the TH350 from the old motor, cleaned it up, changed the tranny mount. - Moved the tranny crossmember forward to pick up the tailshaft. Or maybe I'd just reinstalled it in the wrong place the first time... Here's what I need to know: - The shifter linkage doesn't line up now. Looks like the bracket unbolts off the frame and moves forward (there are holes there already) but the rod that connects to the steering column doesn't look like it'll work. Its drilled for a cotter pin at the linkage, and tapered down at the other end to fit the connector at the column. Do I need a different rod, or am I missing something? - The torque converter is tight against the flexplate, and won't turn to align the bolt holes. Probably should have bolted that together before installing the motor/tranny, but I figured that's be easier to do with the truck on the lift. When I put the TC on, I rotatated it until I heard 2 thunks, so I though it was seated. Dose a V8 use a different TC than a straight six, or did I just screw up the install? - Will the driveshaft fit? I haven't checked this yet, but if the tranny moved forward because the V8 is shorter, will the driveshaft be too short? Or did V8s and 6s use the same driveshaft? I figure somebody here has done the same swap, and lived through this already. I'd sure appreciate any advice I can get. __________________ - Just a dad helping his 16 year old build a '72 he bought himself

06-24-2018, 05:48 PM	#2
rjs53 Registered User Join Date: Jan 2010 Location: nevada Posts: 649	Re: Need V8 Swap Help Just a question, did you make sure the torque convertor is in the transmission all the way? On the th350 you need to spin the convertor until it goes in a couple clicks, if not you'll brake the pump. __________________ 2003 Dodge 2500 1969 C10 2014 Camaro SS/RS/1LE

06-24-2018, 06:31 PM	#3
Steve78LT Registered User Join Date: Jun 2018 Location: Massachusetts Posts: 4	Re: Need V8 Swap Help Yup. Heard 2 thunks. Now, whether it slid forward in the process of installing the tranny on the motor, I can't say for sure. Before I pull the tranny out, I just wanted to make sure that both motors use the same converter. __________________ - Just a dad helping his 16 year old build a '72 he bought himself

06-24-2018, 07:19 PM	#4
Getter-Done Senior Member Join Date: Dec 2009 Location: TN. Posts: 8,442	Re: Need V8 Swap Help Welcome First thing your torque convertor probably slipped out on you. Second thing this link below may answer some of your other questions. http://67-72chevytrucks.com/vboard/s...ds+on+a+350+v8 __________________ ________________________________________________________________________________________ ____________________________________________ 84 Chevy K-20 63 Impala (my high school car) http://67-72chevytrucks.com/vboard/s...Crew Cab Build



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