Engine and tranny swapping questions... - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Matt_305 · 07-02-2005, 08:58 PM

My truck (81 gmc lwb 1500) currently has the 250ci straight six mated to a 3 speed auto tranny, my other truck (85 gmc lwb 1500) has a 305V8 mated to an SM465.
1)Are the drive shafts the same length or compatible? (305 has 2 piece 250 1 piece)
2)Is the clutch pedal mechanism and clutch fluid resevoir etc hard to hook up?
3)Is the shifter hard to line up through the floor?
4)Any other difficulties I should know about?
5) Are hoses and wiring etc. hard to figure out and make compatible?
The front ends of both trucks are already torn down except the front bulkhead I guess you'd call it (what supports the rad). Thank you for your help sorry to ask so many questions but I'm a bit of a newbie at the whole thing but have come this far and feel hey why not go all the way. Thanks again.
Matt

Matt_305 · 07-04-2005, 05:44 PM

bump

*1FaastC10* · 07-04-2005, 06:02 PM

shoudl be a direct bolt in, save for the clutch master cylinder mounting holes, and the shifter hole. i know there are dimples in the firewall to show you where to mount the master cylinder, my 86 had them, as did my buddy's 84. since you have both trucks, you can take measurements from one and transfer the parts to the other truck. should be a very painless swap.

the baron · 07-05-2005, 05:07 AM

Hi Matt ,

what are your intentions precisely ?

do you want to put the 305 on the auto tranny ?

an engine swap from a truck to another is easier than swapping the whole transmission , fitting pedals , boring holes to allow the fitting of the poke , etc...

greetzzzz

the Baron

Matt_305 · 07-05-2005, 07:53 PM

My intentions are to change the engines and transmissions so yes putting in the standard still on the 305,I must do everything the hard way, still wondering are the driveshafts compatible? could the standard go to the single piece?

*1FaastC10* · 07-05-2005, 09:24 PM

check the part numbers on both trucks for the rear u joint. i'd almost bet they're the same. the driveshafts should be fine if both trucks are the same wheelbase, just keep the driveshaft with the trans it was originally mated to.

Matt_305 · 07-06-2005, 06:36 PM

Hey thanks for the help guys, sounds good, don't think I'll get too lost.

Matt_305 · 07-07-2005, 08:02 PM

I guess I've changed my plans due to time contrants from work I will only be switching motors for now and perhaps transmissions later. Is there any added complications from doing this I should know about it looks pretty straight forward, thanks again
Matt

Matt_305 · 07-08-2005, 02:09 PM

bump

07-02-2005, 08:58 PM	#1
Matt_305 Registered User Join Date: Dec 2003 Location: Nova Scotia, Canada Posts: 102	Engine and tranny swapping questions... My truck (81 gmc lwb 1500) currently has the 250ci straight six mated to a 3 speed auto tranny, my other truck (85 gmc lwb 1500) has a 305V8 mated to an SM465. 1)Are the drive shafts the same length or compatible? (305 has 2 piece 250 1 piece) 2)Is the clutch pedal mechanism and clutch fluid resevoir etc hard to hook up? 3)Is the shifter hard to line up through the floor? 4)Any other difficulties I should know about? 5) Are hoses and wiring etc. hard to figure out and make compatible? The front ends of both trucks are already torn down except the front bulkhead I guess you'd call it (what supports the rad). Thank you for your help sorry to ask so many questions but I'm a bit of a newbie at the whole thing but have come this far and feel hey why not go all the way. Thanks again. Matt __________________ 1981 GMC Sierra 1500 4.1L I6 1985 GMC Sierra 1500 5.0L V8 (Parts Truck)

07-04-2005, 05:44 PM	#2
Matt_305 Registered User Join Date: Dec 2003 Location: Nova Scotia, Canada Posts: 102	bump __________________ 1981 GMC Sierra 1500 4.1L I6 1985 GMC Sierra 1500 5.0L V8 (Parts Truck)

07-05-2005, 05:07 AM	#4
the baron Registered User Join Date: Mar 2003 Location: Liège , Belgium Posts: 263	Hi Matt , what are your intentions precisely ? do you want to put the 305 on the auto tranny ? an engine swap from a truck to another is easier than swapping the whole transmission , fitting pedals , boring holes to allow the fitting of the poke , etc... greetzzzz the Baron __________________ 1982 Suburban 2WD , 260ci Olds engine,TH400 , will get a 1979 front clip , might be ready in ... 2016 1985 Chevy Van ( 305/350 ) , "Kellogg" equipped , my actual D.D. 1960 Girl Friend , frame still good , body has some dents

07-05-2005, 07:53 PM	#5
Matt_305 Registered User Join Date: Dec 2003 Location: Nova Scotia, Canada Posts: 102	My intentions are to change the engines and transmissions so yes putting in the standard still on the 305,I must do everything the hard way, still wondering are the driveshafts compatible? could the standard go to the single piece? __________________ 1981 GMC Sierra 1500 4.1L I6 1985 GMC Sierra 1500 5.0L V8 (Parts Truck)

07-06-2005, 06:36 PM	#7
Matt_305 Registered User Join Date: Dec 2003 Location: Nova Scotia, Canada Posts: 102	Hey thanks for the help guys, sounds good, don't think I'll get too lost. __________________ 1981 GMC Sierra 1500 4.1L I6 1985 GMC Sierra 1500 5.0L V8 (Parts Truck)

07-04-2005, 06:02 PM	#3
1FaastC10 Account Suspended Join Date: Oct 2002 Location: Elkhart, IN Posts: 6,400	shoudl be a direct bolt in, save for the clutch master cylinder mounting holes, and the shifter hole. i know there are dimples in the firewall to show you where to mount the master cylinder, my 86 had them, as did my buddy's 84. since you have both trucks, you can take measurements from one and transfer the parts to the other truck. should be a very painless swap.

07-05-2005, 09:24 PM	#6
1FaastC10 Account Suspended Join Date: Oct 2002 Location: Elkhart, IN Posts: 6,400	check the part numbers on both trucks for the rear u joint. i'd almost bet they're the same. the driveshafts should be fine if both trucks are the same wheelbase, just keep the driveshaft with the trans it was originally mated to.

07-07-2005, 08:02 PM	#8
Matt_305 Registered User Join Date: Dec 2003 Location: Nova Scotia, Canada Posts: 102	I guess I've changed my plans due to time contrants from work I will only be switching motors for now and perhaps transmissions later. Is there any added complications from doing this I should know about it looks pretty straight forward, thanks again Matt __________________ 1981 GMC Sierra 1500 4.1L I6 1985 GMC Sierra 1500 5.0L V8 (Parts Truck)

07-08-2005, 02:09 PM	#9
Matt_305 Registered User Join Date: Dec 2003 Location: Nova Scotia, Canada Posts: 102	bump __________________ 1981 GMC Sierra 1500 4.1L I6 1985 GMC Sierra 1500 5.0L V8 (Parts Truck)



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