swaping in a 454 bbc

1977moneypit · 12-04-2004, 02:07 PM

I am probably going to be swaping a 454 into my 77 chevy k10...it has a 400 sb in it right now but has been giving me so many problems....blow by, loss of compression...and i think think the block might even be cracked because of white smoke out of the pipes. My question is will I be able to just swap in the 454 without any fear of trashing the tranny...I have a th350 w/np 203 t-case. I have read abunch of threads saying that you need to beef up the th350 for people that have 600hp big blocks. But, I am not looking to drag my truck, I just figure if im gunna get another motor I might as well go with a big motor that is gunna sound mean. All I plan on doing is just boring out the block to get whatever lip is there and then just go with a basically stock piston, new gaskets and headers. Will this pretty much stock 454 be alright against my new/stock th350?

warrenp · 01-27-2005, 05:34 AM

they claim the turbo 400 was a stronger trans than the 350.
you can beef up a turbo 350 fairly cheep!
i think it could probably take it.
i was reading an artical once on a 700r4 was bolted to a zr1 vette engine
those supposed to have some good torque thinking 400-500 lbs

the local tranny rebuiler here sees to think a turbo 350 is a better trans than a 700r4?
i have alwasy been a fan of the 700r4 because of the over drive.
but alot of people do not seem to like them.

JIM · 05-27-2005, 09:38 PM

I don't know if you've allready done the engine swap by now, but the engine mount brackets are taller on big block 73-87 GMC/Chevy trucks. If you don't change them you will most likly have rear driveshaft u-joint breakage issues on a short weelbase truck (Blazer/Jimmy) because of the poor tailshaft angle. Also if headers are used they may hit the frame. I discovered this on a customers 81 1/2 ton Blazer 4x4 454, and the Doug Thorley headers we were installing hit the frame on both sides of the vehicle. After installing the taller mount brackets the driveshaft angle was much better. My customer told me that he had rear driveline problems with the truck ever since swaping in the big block.
What to look for:
I don't think the big block was offered on the Blazer from the factory so look for a big block Duelly or Suburban in the wreaking yard. The parts you need are between the K-member and the motor mounts.

932500 · 09-11-2005, 09:15 AM

Who told you the mounts are different?.Go slap them. This is a straight swap, and your trans will be fine. A stock 454 doesnt get anywhere close to 400 hp let alone 600. Just drop it in and drive. Nothing else required or needed.

jobberone · 09-23-2005, 07:29 PM

wrote a long message but somehow I managed to trash it.

Your 400 needs to be rebuilt. The smoke sounds like rings and/or bad valve stems.

Why not spend your money on a rebuild and do some head work, bigger cam, nice intake, and a proper carb. Spend some money of a 4L60E tranny and get an extra gear. Put it a nice suspension and rear end. Some paint, tires, digital instruments. U get the picture.

If you really want a BBC PM me and I have a very nice streetable one suitable for you. Or I can help you build a BBC that's good for the street and easier on your truck and pocketbook. A 450HP 454 is a very different animal that a 600HP one. But they both have gobs of torque which is what trucks love. JMO

chevyguy · 09-24-2005, 03:55 PM

I agree the 400 is a great motor. The white smoke is probally a blown head gasket, or a ckacked head. The earlier 400 heads were know for that. i say rebuild it and install a set of L31 vortec heads and that big small block will breath. You wont be dissappointed. Also small block parts are alot easier and cheaper to come by.

jobberone · 09-24-2005, 05:25 PM

If it's running decent it probably doesn't have a blown head gasket. If the oil is milky and it runs badly then maybe. But constant puffs of white smoke are usually rings. Intermittent puffs when accelerating are probably valve/stems. JMO.

It's cheaper to rebuild those 400s and u can get some decent torque from those big small blocks. Lots of ways to play with the bottom end as well.

chevyguy · 09-24-2005, 06:29 PM

Yes your right if it is in fact smoke. just thought since he mentioned a cracked block we were talking steam not smoke. But I disagree about the head gasket always causing milky oil. If it leaks into the cylinder then no you wont see milky oil, just a steamy exhaust, and as i mentioned earlier those heads are known for cracks arouns the seats which usually dump antifreeze into the cylinder. I agree with the staying with the small block. I love the 400 sbc

jobberone · 09-25-2005, 05:36 PM

Quote:

Originally Posted by chevyguy

Yes your right if it is in fact smoke. just thought since he mentioned a cracked block we were talking steam not smoke. But I disagree about the head gasket always causing milky oil. If it leaks into the cylinder then no you wont see milky oil, just a steamy exhaust, and as i mentioned earlier those heads are known for cracks arouns the seats which usually dump antifreeze into the cylinder. I agree with the staying with the small block. I love the 400 sbc

You're right. Doesn't always have to be thru a water main or steam hole but the chances are very high. It needs to be torn down and then you'll know. Then you can play with it.

chevyguy · 09-26-2005, 10:57 PM

I am trying to remember the casting number of those 400 194/150 heads that were problematic in this region. I will look tomorrow.I think it started with an 882, but dont quote me.

12-04-2004, 02:07 PM	#1
1977moneypit Junior Member Join Date: Dec 2004 Posts: 2	swaping in a 454 bbc I am probably going to be swaping a 454 into my 77 chevy k10...it has a 400 sb in it right now but has been giving me so many problems....blow by, loss of compression...and i think think the block might even be cracked because of white smoke out of the pipes. My question is will I be able to just swap in the 454 without any fear of trashing the tranny...I have a th350 w/np 203 t-case. I have read abunch of threads saying that you need to beef up the th350 for people that have 600hp big blocks. But, I am not looking to drag my truck, I just figure if im gunna get another motor I might as well go with a big motor that is gunna sound mean. All I plan on doing is just boring out the block to get whatever lip is there and then just go with a basically stock piston, new gaskets and headers. Will this pretty much stock 454 be alright against my new/stock th350?

05-27-2005, 09:38 PM	#3
JIM Junior Member Join Date: May 2005 Location: California Posts: 2	Swaping in a 454 I don't know if you've allready done the engine swap by now, but the engine mount brackets are taller on big block 73-87 GMC/Chevy trucks. If you don't change them you will most likly have rear driveshaft u-joint breakage issues on a short weelbase truck (Blazer/Jimmy) because of the poor tailshaft angle. Also if headers are used they may hit the frame. I discovered this on a customers 81 1/2 ton Blazer 4x4 454, and the Doug Thorley headers we were installing hit the frame on both sides of the vehicle. After installing the taller mount brackets the driveshaft angle was much better. My customer told me that he had rear driveline problems with the truck ever since swaping in the big block. What to look for: I don't think the big block was offered on the Blazer from the factory so look for a big block Duelly or Suburban in the wreaking yard. The parts you need are between the K-member and the motor mounts. Last edited by JIM; 05-27-2005 at 09:47 PM.

09-24-2005, 03:55 PM	#6
chevyguy Senior Member Join Date: Sep 2005 Location: ALABAMA Posts: 3,370	I agree the 400 is a great motor. The white smoke is probally a blown head gasket, or a ckacked head. The earlier 400 heads were know for that. i say rebuild it and install a set of L31 vortec heads and that big small block will breath. You wont be dissappointed. Also small block parts are alot easier and cheaper to come by. __________________ Friends dont let friends use body lifts USMC 92-96 USCG 98 to present

09-24-2005, 06:29 PM	#8
chevyguy Senior Member Join Date: Sep 2005 Location: ALABAMA Posts: 3,370	Yes your right if it is in fact smoke. just thought since he mentioned a cracked block we were talking steam not smoke. But I disagree about the head gasket always causing milky oil. If it leaks into the cylinder then no you wont see milky oil, just a steamy exhaust, and as i mentioned earlier those heads are known for cracks arouns the seats which usually dump antifreeze into the cylinder. I agree with the staying with the small block. I love the 400 sbc __________________ Friends dont let friends use body lifts USMC 92-96 USCG 98 to present

09-26-2005, 10:57 PM	#10
chevyguy Senior Member Join Date: Sep 2005 Location: ALABAMA Posts: 3,370	I am trying to remember the casting number of those 400 194/150 heads that were problematic in this region. I will look tomorrow.I think it started with an 882, but dont quote me. __________________ Friends dont let friends use body lifts USMC 92-96 USCG 98 to present

01-27-2005, 05:34 AM	#2
warrenp Banned Join Date: Oct 2004 Location: maine Posts: 49	they claim the turbo 400 was a stronger trans than the 350. you can beef up a turbo 350 fairly cheep! i think it could probably take it. i was reading an artical once on a 700r4 was bolted to a zr1 vette engine those supposed to have some good torque thinking 400-500 lbs the local tranny rebuiler here sees to think a turbo 350 is a better trans than a 700r4? i have alwasy been a fan of the 700r4 because of the over drive. but alot of people do not seem to like them.

09-11-2005, 09:15 AM	#4
932500 Banned Join Date: Jul 2005 Location: Oregon Posts: 51	Who told you the mounts are different?.Go slap them. This is a straight swap, and your trans will be fine. A stock 454 doesnt get anywhere close to 400 hp let alone 600. Just drop it in and drive. Nothing else required or needed.

09-23-2005, 07:29 PM	#5
jobberone Full Member Join Date: Sep 2005 Posts: 21	wrote a long message but somehow I managed to trash it. Your 400 needs to be rebuilt. The smoke sounds like rings and/or bad valve stems. Why not spend your money on a rebuild and do some head work, bigger cam, nice intake, and a proper carb. Spend some money of a 4L60E tranny and get an extra gear. Put it a nice suspension and rear end. Some paint, tires, digital instruments. U get the picture. If you really want a BBC PM me and I have a very nice streetable one suitable for you. Or I can help you build a BBC that's good for the street and easier on your truck and pocketbook. A 450HP 454 is a very different animal that a 600HP one. But they both have gobs of torque which is what trucks love. JMO

09-24-2005, 05:25 PM	#7
jobberone Full Member Join Date: Sep 2005 Posts: 21	If it's running decent it probably doesn't have a blown head gasket. If the oil is milky and it runs badly then maybe. But constant puffs of white smoke are usually rings. Intermittent puffs when accelerating are probably valve/stems. JMO. It's cheaper to rebuild those 400s and u can get some decent torque from those big small blocks. Lots of ways to play with the bottom end as well.

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