what's necessary to do a big block swap?

[Sublvr72]

My buddy is sending a 89 chevy 2500 to the scrapper and it's got a 454 and turbo 400 trans that he's gonna give me for cheap. What's needed to get this swapped into my truck?

are the motor mounts the same or will they need to be changed? Any other problems I might run into?

I'm trying to get everything together before the swap so it goes as seamlessly as possible.


I'm already pricing out intake manifolds to swap out the TBI back to carb, and I'm looking for some headers as well.

[leddzepp]

I've got some BB headers and BB motor mounts if you decide to go that route...others will chime in with exactly what is needed, if anything else.

[Sublvr72]

Originally Posted by leddzepp

I've got some BB headers and BB motor mounts if you decide to go that route...others will chime in with exactly what is needed, if anything else.

what do you want for them?

[70stroker]

when i was doing this swap in my 70gmc 2wd i was searching around also. everyone told me they were differnet motor perches. I measured 5 times and they seemed the same to me. So i put it in just to see. I have had no problems runnin my perches off my small block. for what its worth.

[Fitz]

Originally Posted by Sublvr72

My buddy is sending a 89 chevy 2500 to the scrapper and it's got a 454 and turbo 400 trans that he's gonna give me for cheap. What's needed to get this swapped into my truck?

are the motor mounts the same or will they need to be changed? Any other problems I might run into?

I'm trying to get everything together before the swap so it goes as seamlessly as possible.


I'm already pricing out intake manifolds to swap out the TBI back to carb, and I'm looking for some headers as well.

Aside from motor mounts and frame stands,
be sure to take the entire serpentine belt drive,idler and all of the bracketry power steering pump, A/C compressor, idler and pulleys. You didn’t say which motor you’re running now so I’ll assume a small block, which means you’ll need a larger Radiator. I doubt a fan & fan clutch from 67-72 is going to be compatible with the belt drive on that motor so you may want to think about an electric fan.
The stock power brake booster is 10 in in diameter and is probably going to interfere with the valve cover on that side so you might need a smaller diameter booster if you’re running power brakes. I don’t know which starter you have on that motor but the large housing starters almost fill the exhaust path on the passenger side so you might need a mini starter.

[Nova70]

You can pretty much drop it right in if you wanted to. I would suggest putting BB mounts in as they're a little beefier.

[BB72CHEVKT]

money

[cdowns]

4core radiator is nice for a BB

[Sublvr72]

Originally Posted by Fitz

Aside from motor mounts and frame stands,
be sure to take the entire serpentine belt drive,idler and all of the bracketry power steering pump, A/C compressor, idler and pulleys. You didn’t say which motor you’re running now so I’ll assume a small block, which means you’ll need a larger Radiator. I doubt a fan & fan clutch from 67-72 is going to be compatible with the belt drive on that motor so you may want to think about an electric fan.
The stock power brake booster is 10 in in diameter and is probably going to interfere with the valve cover on that side so you might need a smaller diameter booster if you’re running power brakes. I don’t know which starter you have on that motor but the large housing starters almost fill the exhaust path on the passenger side so you might need a mini starter.

I should probably clarify that... I've got a 307 and 3 speed. The goal is to pull out the motor and trans in my truck, and bolt in the motor and trans from the 89. The 454 is being pulled from a running truck so everything is there. Serpentine system, accessories, mechanical fan, etc.

My truck is currently drum brakes so the booster shouldn't be a problem yet.

So as for the motor mounts, the big block will fit right into the small block mounts?

[cdowns]

you'll need to remove the manual tranny crossmember and get an autotranny crossmember// you'll probally need to have a driveshaft built// when removing from the donor vehicle take the driveshaft so you can at least salvage the yoke that goes to the tranny

[Fitz]

Originally Posted by Sublvr72

I should probably clarify that... I've got a 307 and 3 speed. The goal is to pull out the motor and trans in my truck, and bolt in the motor and trans from the 89. The 454 is being pulled from a running truck so everything is there. Serpentine system, accessories, mechanical fan, etc.

My truck is currently drum brakes so the booster shouldn't be a problem yet.

So as for the motor mounts, the big block will fit right into the small block mounts?

You will still need the big block frame stands and mounts....the small block mounts will bolt onto your 454 but the frame stands are too close together to accept them.

[67/72junkie]

you can use 73 up frame stands and clam shell engine mounts.only requires drilling a couple holes .save your self some cash.

[Sublvr72]

ok, I found some big block frame mounts and some headers from a member here. Aside from that and the trans cross member, the rest is all bolt on?

[67/72junkie]

bb auto trans linkage,I have for $75 complete.If you have pwr steering you will need to have the metric ends on the sector end of the lines changed to standard.

[Sublvr72]

got the motor and trans pulled from the donor truck!

Now to pull my 307 and 3 speed





the TH400 was rebuilt 4 years ago and hasn't been driven since.

[LONGHAIR]

You are going to need to swap in a radiator that has the auto trans cooler too....and what about the induction system? Are you planning on running that TBI or converting to a carburetor?

These "for cheap" swaps have a tendancy to get spendy...

[Hottrucks]

your going to need to wire up the trans shift switch...( it maybe on the peddle of the parts truck)..do your self a BIG favor..take a week and clean and paint everything...put you new carb on get rid of all the polution stuff and if your going to run the stock exhaust maniford put new studs in..it should look like this...it will make the install go much easyier

waiting for the pics to upload I remebered the feed for the HEI needs to be 12V and check the oil sending unit so you can hook it up to your gauge..save the line that gos to the power barke booster you'll kick yourself later if you don't..its the little things that will slow you down and make for 10 trips to the parts store

notice the new mounts and stands sitting there

[junkyardjohn]

Originally Posted by 67/72junkie

you can use 73 up frame stands and clam shell engine mounts.only requires drilling a couple holes .save your self some cash.

SORRY DONALD.. I HAVE TO DISAGREE. 73 UP STANDS ARE TALLER & REQUIRE ABOUT A 1" SPACER ON THE TOP OF THE FRAME RAIL ON OEM CROSSMEMBER ASSY.s (BEEN THERE.. DONE THAT). NOW IF THE CROSSMEMBER ASSY. HAS BEEN REPLACED WITH A 73 UP TO GET THE DISC. BRAKES... SURE.. THEY'LL BOLT RIGHT IN. OTHERWISE PEOPLE WOULD BE USING THESE $20 STANDS INSTEAD OF PAYING $200 FOR THE 72 ONLY BB STANDS. JOHN (WHEN ARE YOU COMMING THIS WAY TO BUY ME THAT STEAK DINNER & A BEER?) JOHN

[Sublvr72]

Originally Posted by LONGHAIR

You are going to need to swap in a radiator that has the auto trans cooler too....and what about the induction system? Are you planning on running that TBI or converting to a carburetor?

These "for cheap" swaps have a tendancy to get spendy...

I'm aware of the radiator, I've got a single core radiator at the moment so that's gonna be first to go when the motor gets swapped. I'm going to convert to carburetor, so intake and carb are on the list as well.

I already realize this isn't going to be a cheap swap, but I guess the end result should be worth it.

[Hottrucks]

wish you where closer I have a bunch of parts to get you rolling they arn't great but usable things like a straight auto column ( your going to need the linkage parts or you could go with a locar floor shifter and leave yours)a 3 core rad and auto X memeber...dam...but most of that can be found in the bone yards or from local memebers...

[Shyguy]

When we put a '73 454 in my '71 with a old style 4 speed we used BB motor mounts and stands from a '74 C-20.

We did have to drill new holes, but the engine and transmission works great together without having to change the drive shaft.

One mistake we made is we used the stock starter instead of a mini starter so the engine has heat soak problems.

Danny

[Sublvr72]

big block motor mounts.... check
big block headers.... check
big block.... check
trans.... check

still need...

intake manifold
carburetor
fan
auto x member
fuel pump
AT radiator

[sameyrasmea72]

A BB/th400 truck also had a high hump cab floor. I don't know if you will have clearence problems or not, but there has to be some reason the factory BB trucks have a high hump.

[Sublvr72]

hmmm... I guess we shall see when it goes in... Worse case I'll cut the floor and raise it up

[fishingjred73]

Originally Posted by sameyrasmea72

A BB/th400 truck also had a high hump cab floor. I don't know if you will have clearence problems or not, but there has to be some reason the factory BB trucks have a high hump.

Originally Posted by Sublvr72

hmmm... I guess we shall see when it goes in... Worse case I'll cut the floor and raise it up

No need look here 454/400 with low hump cab page 5 post #122
http://67-72chevytrucks.com/vboard/s...=271489&page=5