?'s for 454 swap in a 72 4x4 Blazer - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Big Bad 1972 Blazer · 02-06-2005, 02:18 PM

Alright, now that I've almost got my 454 rebuilt, punched .060" and stroked .250" with a bunch of other goodies...I'm grunting right now

(it'll be dyno'd soon), it's time to get the chassis ready to receive the beast. I'm looking for tips from others who've swapped in a BBC into a 4x Blazer. Towers & mounts used? Did you use a 73+ cross member? Clearance issues? Mods needed?

Here's some of the basics as to what I'm running w/ the BB...
TH350 W/ NP205
3" body, 4" suspension lift
tall valve covers for rocker arm clearance
Hedman long headers

Thanks in advance....I'll post pics when I'm done.

6772king · 02-06-2005, 03:41 PM

in mine I just used all the factory stuff and moved everthing ahead a couple of inches,,, downfall is you have to get all new driveshafts made,,, but mine were junk anyhow,,,they hit the road 1 two many times!!!!LOL!! and that was just with a little 327!! the 3 inch body lift will work in you favor also ,,,I can take pics of both setups ( with and without body lifts) if you want,,I have very tall valve covers on my blazer with no body lift

Big Bad 1972 Blazer · 02-06-2005, 04:21 PM

Quote:

Originally Posted by 6772king

in mine I just used all the factory stuff and moved everthing ahead a couple of inches,,, downfall is you have to get all new driveshafts made,,, but mine were junk anyhow,,,they hit the road 1 two many times!!!!LOL!! and that was just with a little 327!! the 3 inch body lift will work in you favor also ,,,I can take pics of both setups ( with and without body lifts) if you want,,I have very tall valve covers on my blazer with no body lift

Did you shift everything forward to get enough clearance to the firewall? If so, where were the tight spots? Right now, I'll tend to massage the firewall to get enough clearance. I'd rather not spend more $$$ on my driveshafts, although it's not a big deal. I had to replace mine not to long ago due to an "unfortunate incident" with a log...lol Please post the pics with the body lift if you have them handy...gracias

orangeuavol · 02-06-2005, 07:18 PM

Take a look at the pics in my signature. I swapped the SB w/ a 402 BB. We used the SB mounts, existing cross member, and exhaust manifolds from a 72 Monte Carlo. All I did was recess two pockets in the firewall for valve cover clearance. Its a tight fit but was almost a drop in replacement. I will however have to have new driveshafts made because I put a TH400 and NP205 in place of the three speed dana 20 combo.

6772king · 02-06-2005, 08:19 PM

if you dont mind pounding the firewall in you wont have to move everthing ahead,,,I didnt want to do that,,,l'll try to get some pics tommarow,,, if I forget ,pm meand tell me i'm a a$$hole for forgeting LOL!!!

MAC67 · 02-06-2005, 11:41 PM

this is the 468 i dumped into mine , i pulled the 350 , kncoked in to divits with a small hammer for valve cover clearance and walla bb blazer , it didnt bother me custom hammering the firewall ha ha ha , you can barely see them because they are hidden by the valve covers mostly heres a couple pics , i know theyr not real good

**Yukon Jack** · 02-07-2005, 11:11 AM

You will find some people have put bb's in their trucks and K5's with little to no modification and others that have to do alot. I fell in the "alot" catagory. Burt4x4 has a recent thread showing his bb he just installed - he hardly had to do any modification. I don't know why it fits so easily for some and not for others.

Here are pics of the modifications I had to make. And this is with a body lift. Would have taken serious pounding with a hammer to make the necessary clearance for me and these are short valve covers.

Here is a link to my webpage showing more pics and info on my bb swap

Big Block Swap

Big Bad 1972 Blazer · 02-07-2005, 10:51 PM

Thanks guys for the pics, tips, & links (my keyboard is acting up now from drooling at your rides).

The valve cover clearance was what I was worried about. Based on what I see, I think once I yank the SB, I'm just going to break out the cutting wheel and create a little clearance in the firewall....no reason not to. I've got a really good idea as to how much to hack out based on everybody's feedback. Murphy's law states that I'll probably be on the "lots of work side", so I might as well build in extra clearance in that area. It looks like nothing that a little fab work can't cure...and it if that doesn't work, I'll break out the 5lb hammer

mister.freeze · 02-07-2005, 11:22 PM

The Fox used to have a 454. Originally 350, then 454, back to 350, and now 383. No recesses were ever made to fenders or firewall. In fact, my SB sits on the 454 mounts. It looks like the original crossmember rivets were ground off, and it was moved AFT a ways and BOLTED back in. My distributor is tight to the firewall, and I've got about 8" between the pulleys and the radiator. If you need pix, holler.

Burt4x4 · 02-08-2005, 04:11 PM

I used a '74 454 & '73+ SBC Crossmember(makes oil pan removable without moving the engine)

Kinda hard to see the firewall as I painted everything black, but I did have to BANG BANG BANG on the firewall just a lil bit to clear the driver's side head.

73+ crossmember sits infront of the oilpan instead of under it.

Some have had to notch the frame with a half moon shape to clear header pipe but mine is 1/8th away so i didn't have to notch it.
I plan on starting my 454 for the first time this Saturday

Good Luck
Burt

Big Bad 1972 Blazer · 02-08-2005, 08:04 PM

It really doens't suprise me to hear about so many differing accounts as to how much modifying needs to be drop in a BB, especially around the firewall. Shoot, back then, you could measure build variation in the assembly plants with a yard stick. Roll the dice....

Burt...good luck firing up the BB this weekend. I'm jealous, I 've got a few more weeks of work before I can crank mine over.

02-06-2005, 02:18 PM	#1
Big Bad 1972 Blazer Registered User Join Date: Jan 2005 Location: Armada, MI 48188 Posts: 83	?'s for 454 swap in a 72 4x4 Blazer Alright, now that I've almost got my 454 rebuilt, punched .060" and stroked .250" with a bunch of other goodies...I'm grunting right now (it'll be dyno'd soon), it's time to get the chassis ready to receive the beast. I'm looking for tips from others who've swapped in a BBC into a 4x Blazer. Towers & mounts used? Did you use a 73+ cross member? Clearance issues? Mods needed? Here's some of the basics as to what I'm running w/ the BB... TH350 W/ NP205 3" body, 4" suspension lift tall valve covers for rocker arm clearance Hedman long headers Thanks in advance....I'll post pics when I'm done.

02-06-2005, 03:41 PM	#2
6772king Registered User Join Date: Feb 2002 Location: grove city pa usa Posts: 628	in mine I just used all the factory stuff and moved everthing ahead a couple of inches,,, downfall is you have to get all new driveshafts made,,, but mine were junk anyhow,,,they hit the road 1 two many times!!!!LOL!! and that was just with a little 327!! the 3 inch body lift will work in you favor also ,,,I can take pics of both setups ( with and without body lifts) if you want,,I have very tall valve covers on my blazer with no body lift __________________ 67 chevy short step 2wd 427 71 chevy short fleet 4x4 396 72 gmc jimmy 2wd 377 71 chevy blazer 4x4 454 69 chevy longhorn 5.9l cummins 72 chevy 400 2wd custom camper 67 chevy lwb 4x4 454-in pieces 67 chevy panel soon 4x4-400 67 gmc dump 4x4 1 ton-305 WTF!! 72 chevy 3/4 ton 4x4 burb 350 70 chevy panel 2wd 302 5 speed tko "THERE IS NO REPLACMENT FOR DISPLACMENT"!!!!!!!

02-06-2005, 07:18 PM	#4
orangeuavol GO VOLS! Join Date: May 2001 Location: Knoxville, TN Posts: 725	Take a look at the pics in my signature. I swapped the SB w/ a 402 BB. We used the SB mounts, existing cross member, and exhaust manifolds from a 72 Monte Carlo. All I did was recess two pockets in the firewall for valve cover clearance. Its a tight fit but was almost a drop in replacement. I will however have to have new driveshafts made because I put a TH400 and NP205 in place of the three speed dana 20 combo. __________________ http://1972blazer.shutterfly.com/<= blazer build pics It's called golf because all the other four letter words were taken. It's easier to ask for forgiveness than for permission.

02-06-2005, 08:19 PM	#5
6772king Registered User Join Date: Feb 2002 Location: grove city pa usa Posts: 628	if you dont mind pounding the firewall in you wont have to move everthing ahead,,,I didnt want to do that,,,l'll try to get some pics tommarow,,, if I forget ,pm meand tell me i'm a a$$hole for forgeting LOL!!! __________________ 67 chevy short step 2wd 427 71 chevy short fleet 4x4 396 72 gmc jimmy 2wd 377 71 chevy blazer 4x4 454 69 chevy longhorn 5.9l cummins 72 chevy 400 2wd custom camper 67 chevy lwb 4x4 454-in pieces 67 chevy panel soon 4x4-400 67 gmc dump 4x4 1 ton-305 WTF!! 72 chevy 3/4 ton 4x4 burb 350 70 chevy panel 2wd 302 5 speed tko "THERE IS NO REPLACMENT FOR DISPLACMENT"!!!!!!!

02-06-2005, 11:41 PM	#6
MAC67 " SHOW ME" Join Date: Jan 2003 Location: shelbyville illinois Posts: 2,624	this is the 468 i dumped into mine , i pulled the 350 , kncoked in to divits with a small hammer for valve cover clearance and walla bb blazer , it didnt bother me custom hammering the firewall ha ha ha , you can barely see them because they are hidden by the valve covers mostly heres a couple pics , i know theyr not real good Attached Images

02-07-2005, 11:11 AM	#7
Yukon Jack Post Whore Join Date: Feb 2000 Location: Rose Hill, KS, USA Posts: 12,683	You will find some people have put bb's in their trucks and K5's with little to no modification and others that have to do alot. I fell in the "alot" catagory. Burt4x4 has a recent thread showing his bb he just installed - he hardly had to do any modification. I don't know why it fits so easily for some and not for others. Here are pics of the modifications I had to make. And this is with a body lift. Would have taken serious pounding with a hammer to make the necessary clearance for me and these are short valve covers. Here is a link to my webpage showing more pics and info on my bb swap Big Block Swap __________________ 1970 Blazer with a 400 sbc and 4" lift 1980 Pontiac Trans Am, 455 Oldsmobile 2012 Kawasaki Concours 14

02-07-2005, 10:51 PM	#8
Big Bad 1972 Blazer Registered User Join Date: Jan 2005 Location: Armada, MI 48188 Posts: 83	Thanks guys for the pics, tips, & links (my keyboard is acting up now from drooling at your rides). The valve cover clearance was what I was worried about. Based on what I see, I think once I yank the SB, I'm just going to break out the cutting wheel and create a little clearance in the firewall....no reason not to. I've got a really good idea as to how much to hack out based on everybody's feedback. Murphy's law states that I'll probably be on the "lots of work side", so I might as well build in extra clearance in that area. It looks like nothing that a little fab work can't cure...and it if that doesn't work, I'll break out the 5lb hammer

02-07-2005, 11:22 PM	#9
mister.freeze Registered User Join Date: Dec 2003 Location: Houston, TX Posts: 734	The Fox used to have a 454. Originally 350, then 454, back to 350, and now 383. No recesses were ever made to fenders or firewall. In fact, my SB sits on the 454 mounts. It looks like the original crossmember rivets were ground off, and it was moved AFT a ways and BOLTED back in. My distributor is tight to the firewall, and I've got about 8" between the pulleys and the radiator. If you need pix, holler. __________________ '72 K5, known as 'the Fox.'

02-08-2005, 04:11 PM	#10
Burt4x4 Registered User Join Date: Feb 2000 Location: Modesto, CA Posts: 1,842	I used a '74 454 & '73+ SBC Crossmember(makes oil pan removable without moving the engine) Kinda hard to see the firewall as I painted everything black, but I did have to BANG BANG BANG on the firewall just a lil bit to clear the driver's side head. 73+ crossmember sits infront of the oilpan instead of under it. Some have had to notch the frame with a half moon shape to clear header pipe but mine is 1/8th away so i didn't have to notch it. I plan on starting my 454 for the first time this Saturday Good Luck Burt __________________ 1972 K5 MPFI454/Sm465/Np205/D60/14FFd/Re-Centerd H1s w/Swamper Iroks

02-08-2005, 08:04 PM	#11
Big Bad 1972 Blazer Registered User Join Date: Jan 2005 Location: Armada, MI 48188 Posts: 83	It really doens't suprise me to hear about so many differing accounts as to how much modifying needs to be drop in a BB, especially around the firewall. Shoot, back then, you could measure build variation in the assembly plants with a yard stick. Roll the dice.... Burt...good luck firing up the BB this weekend. I'm jealous, I 've got a few more weeks of work before I can crank mine over.



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