I6 to 454 Swap?

[81ChevyC10inSC]

I have the Gen IV 454 and a TH400. It came out of a 90 or 91 truck. Other than frame mounts needing to be moved. What other issues do i face? Will the Oil pan clear or do i need a new one? I assume i have to have another set of headers as well? OH to add the engine is complete with all the accessories as well. Any input would be greatly appreciated.

[sweetk30]

for the most part bolt in with the correct frame mounts and engne mounts for the new truck its going in .

and yes exhaust / some small little parts / but to be correct the front coils from I6 to big block are different part #'s for the heavy engine . so if keeping it stock then coil swap . if lowering it try it and or get the correct coils as to desired height .

the rad will need swapped also with the shroud as the big block is a 3 or 4 core over the little one for the 6 cyl .

watch for drive shaft length . and the th400 is prob a 32 spline rear output for the drive shaft yoke over the 27 spline from the old drive-line combo .

[tucsonjwt]

I don't know about the later models, but my 73 454 and my current 83 454 both used standard V8 truck radiators which were 2 core, but they were thicker than most radiators. The one I currently have in the 83 came from AutoZone and is a thicker 2 core aluminum and plastic one from Spectra. It cools fine in the 100+ degree desert heat. I have given up on copper/brass radiators.

Personally, I would stay away from headers, since the BB takes up a lot of under hood space as it is, but I know a lot of people like headers anyway.

[81ChevyC10inSC]

Originally Posted by sweetk30

for the most part bolt in with the correct frame mounts and engne mounts for the new truck its going in .

and yes exhaust / some small little parts / but to be correct the front coils from I6 to big block are different part #'s for the heavy engine . so if keeping it stock then coil swap . if lowering it try it and or get the correct coils as to desired height .

the rad will need swapped also with the shroud as the big block is a 3 or 4 core over the little one for the 6 cyl .

watch for drive shaft length . and the th400 is prob a 32 spline rear output for the drive shaft yoke over the 27 spline from the old drive-line combo .

I plan on lowering the truck a little, not slamming it. So i might be looking at replacing the front coils anyway. So i would need a new Yoke if i went with the th400 and maybe even a shorter drive shaft is what i am hearing?

[CarolinaHD]

Which l6 engine do you have now?

[81ChevyC10inSC]

Originally Posted by CarolinaHD

Which l6 engine do you have now?

The 4.1L 250cid

[87 STEPPER]

I'm not sure what the roads are like in Greer but if you drop that rat motor in your truck and don't change your front springs your gonna bottom out your suspension and maybe wipe out your lower control arms.

If your gonna lower the truck do it the correct way and either get drop spindles or dropped coil springs for a BBC C10. Don't use the weight of the engine to lower the vehicle and expect it to work like it was designed to.

[sweetk30]

Originally Posted by 87 STEPPER

I'm not sure what the roads are like in Greer but if you drop that rat motor in your truck and don't change your front springs your gonna bottom out your suspension and maybe wipe out your lower control arms.

If your gonna lower the truck do it the correct way and either get drop spindles or dropped coil springs for a BBC C10. Don't use the weight of the engine to lower the vehicle and expect it to work like it was designed to.

x2

[81ChevyC10inSC]

Originally Posted by 87 STEPPER

I'm not sure what the roads are like in Greer but if you drop that rat motor in your truck and don't change your front springs your gonna bottom out your suspension and maybe wipe out your lower control arms.

If your gonna lower the truck do it the correct way and either get drop spindles or dropped coil springs for a BBC C10. Don't use the weight of the engine to lower the vehicle and expect it to work like it was designed to.

Agree 100%. I will lower it with spindles and i will replace the coils. I dont need to bounce for an hour after hitting a bump.

[81ChevyC10inSC]

Just an update that the I6 is out and the 454 is resting in place. Working through the TH400 conversion at this point. Hope to have it up and going by end of the week.

[sweetk30]

dont forget the kickdown switch on the gas pedal mount under the dash for the th400

[lobuck64]

Hey just done same swap in my 73 swb step few months back send me a pm if you interested in checking it out I'm about hour away from you

[Pano]

Originally Posted by 81ChevyC10inSC

Just an update that the I6 is out and the 454 is resting in place. Working through the TH400 conversion at this point. Hope to have it up and going by end of the week.

What did you use for motor mounts for the 454? I have a 91 454 replacing my my 87 GMC 350. I hope to do it over the winter. Thx

[81ChevyC10inSC]

Originally Posted by Pano

What did you use for motor mounts for the 454? I have a 91 454 replacing my my 87 GMC 350. I hope to do it over the winter. Thx

The I6 used the clam shell style on the frame already. We just moved it to the proper location and then used a set of regular engine brackets as the original ones on the I6 are too long. Cant give an exact part number as we sourced them from parts we had from something else. Pretty sure they are engine brackets that came from a SBC.

[81ChevyC10inSC]

Originally Posted by sweetk30

dont forget the kickdown switch on the gas pedal mount under the dash for the th400

Truck is running now and i must be missing something here. Its a 3 speed TH400 so im not sure why a kickdown switch would be needed as it has no OD. Please feel free to learn me something if i am over looking something here.

[sweetk30]

th400 uses a kickdown switch for the passing gear drop in the trans when you floor it .

th350 uses a cable for this function .



info for pano :

and if swapping a 350 sbc to a 454 chevy its a virtual bolt in swap minus drive brackets for the alt/ p/s pump and such along with the exhaust .

now if your 87 350 is fuel injected like the factory tbi system you will need those parts and computer to make it run correctly . otherwise its a custom burnt chip or carb or aftermarket system .

[legendman]

Originally Posted by 87 STEPPER

I'm not sure what the roads are like in Greer but if you drop that rat motor in your truck and don't change your front springs your gonna bottom out your suspension and maybe wipe out your lower control arms.

If your gonna lower the truck do it the correct way and either get drop spindles or dropped coil springs for a BBC C10. Don't use the weight of the engine to lower the vehicle and expect it to work like it was designed to.

The big block is a about 260 lbs heavier, I doubt he is going to bottom out his suspension. if it's on stock springs

Originally Posted by blkcorvair

I did find this:

Chevy Sprint 993cc L4 147 (55) 24L x 20W x 25H (Suzuki mfr)
Chevy 1.8-2.0 L4 302 (4) (39) "J car" pushrod
Chevy Chevette 1.6 SOHC 300 (4) (39) (also Opel)
Chevy Vega L4 285
Chevy II 153 L4 350
Chevy L6 194-250 440
Chevy L6 292 ---
Chevy L6 216/235 630 (2)
Chevy L6 216/235 615 (88) "265 V8 was 40# lighter than 235"
Chevy V6-90 229, 4.3 425
Chevy V6-60 2.8, 3.1 350 (2)
Chevy small block V8 575 (generic for '60s-'70s motors)
Chevy small block V8 535 (1) ('59 Corvette 283 w/alum. intake)
Chevy LT-5 DOHC 5.7 600 (122)
Chevy L98 5.7 V8 600 (122)
Chevy V8 348/409 620 (1)
Chevy V8 348/408 655 (83)
Chevy big block V8 685 Mark IV
Chevy big block V8 --- Mark V
Chevy 454 675 (10)
Chevy 427 ZL-1 550 (35) all-aluminum, "20# lighter than SB"

[81ChevyC10inSC]

Currently what the truck looks like now

[Palf70Step]

Very Nice!

If you haven't already, I would also look into changing at least your front disk brakes. The 6 normally came with the smaller/thinner rotors. If your changing spindles, get ones that will work with the 1.25" rotor. There is a lot more go in thrat truck now, so some wwhoah would be good.

[81ChevyC10inSC]

Originally Posted by Palf70Step

Very Nice!

If you haven't already, I would also look into changing at least your front disk brakes. The 6 normally came with the smaller/thinner rotors. If your changing spindles, get ones that will work with the 1.25" rotor. There is a lot more go in thrat truck now, so some wwhoah would be good.

Mine actually had the 1.25" rotor. Had to measure them for my spindles. In that pic it is lowered 2" in front and 4" in the rear. Just have larger wheels on it so it doesnt really look like it. Also changed the upper and lower control arms to tubular added a sway bar in the front.

[Palf70Step]

Nice!

[sweetk30]

when i built my rear axle i did the optinial BIG drum size in the rear . had to score a set of 4x4 10 bolt rear backing plates . then i ordered drums / shoes / hd-kit all for the big option size . went together just fine on my older 12bolt rear 5 lug . went from the 2" wide shoe to the 2.75" wide shoe size .

[81ChevyC10inSC]

Originally Posted by sweetk30

when i built my rear axle i did the optinial BIG drum size in the rear . had to score a set of 4x4 10 bolt rear backing plates . then i ordered drums / shoes / hd-kit all for the big option size . went together just fine on my older 12bolt rear 5 lug . went from the 2" wide shoe to the 2.75" wide shoe size .

I have a set of "GM Big Brake" calipers that a guy gave me that i will put on assuming they fit my truck. Might convert the rear to disc but not sure on that yet.