black dawg
1/2 ton status
looking for a set of headers to fit a 455 olds in a 80 blazer. Any ideas??
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CK5
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455 olds headers for blazer
- Thread starter black dawg
- Start date
454Sub
5/8 ton status
That most likely is going to be a hack job. As not very many people install a 455 in a GM like that. You may be able to get some long tubes, grind and cut them to fit, then finish them up how you like. But I highly doubt you will find off the shelf headers to do that. And by hack I mean custom.
I had a Buick 455 I was going to put in a blazer a while back and I was going to build my own headers.
Looked to be the best way. Sanderson made some shortys that will probably work they are center drops so not sure if they will get in the way of motor mounts or not.
I know you can get pre cut flanges for the Olds 455
Looked to be the best way. Sanderson made some shortys that will probably work they are center drops so not sure if they will get in the way of motor mounts or not.
I know you can get pre cut flanges for the Olds 455
MrSchaeferPants
1/2 ton status
Everyone installs a 455 in a GM. Olds is GM
Just ragginBack before I got the K5 bug, I was a big Olds guy. Try www.oldspower.com search their forum for what headers people use. People stuff 455s in G bodies (80s Cutlass) all the time. The engine bay has the same amount of room as a Blazer, but maybe even smaller since it's not a truck, so as far as height you'd probably be even better off.
MrSchaeferPants
1/2 ton status
Browse some G body websites for 455 swaps, keep an eye out for Hooker Header P/N 3203. See how their installs went for those who used that header. It's supposed to be specifically for shoving a big block into a G body so you don't have to fab/alter. NOW, how that'll relate to putting one in a Blazer...
http://www.jegs.com/i/Hooker/520/3203/10002/-1
Another read: 425 in a 73 K5 http://www.oldspower.com/vb/showthread.php?t=31310
So you specifically want headers, not just a stock exhaust mannifold?
http://www.jegs.com/i/Hooker/520/3203/10002/-1
Another read: 425 in a 73 K5 http://www.oldspower.com/vb/showthread.php?t=31310
So you specifically want headers, not just a stock exhaust mannifold?
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I tried a set of used headers on my 74 454 C-10 that I found at a swap meet cheap that were intended for a 70's Chevelle,and they would have worked as far as clearing the chassis,but I never did bolt them up because I found a rusted thru spot on them and decided I didn't want to be dealing with leaky collectors and gaskets on them,went back to stock manifolds instead.....so if you can find a set for a 70's Cutlass 455,I'd say chances are they might wprk,might have to tweak them some maybe..
MrSchaeferPants
1/2 ton status
Yeah I'm fairly anti-headers just because of the problems that can sometimes be associated with them, usually on the less expensive ones. A few extra ponies doesn't make it worthwhile, and I'm not trying to shave 1/8th of a second off my timeslip with a 4x4 lol. Plus they just fit so much easier. I've had a few on my other K5s in the past, more trouble than they're worth. If I had a street/strip car, might be a different story.
How far off are the "Big block" exhaust manifolds from the Small blocks?
As the small block Olds in the C/K was done pretty often due to the 5.7L diesel issues, I wouldn't be surprised if someone didn't make that header, and if there was one with similar bends, but with the big block Olds flange, it might fit.
I'd be careful with car vs. truck applications, the engine crossmember and frame differences would likely result in some nasty clearance issues.
As the small block Olds in the C/K was done pretty often due to the 5.7L diesel issues, I wouldn't be surprised if someone didn't make that header, and if there was one with similar bends, but with the big block Olds flange, it might fit.
I'd be careful with car vs. truck applications, the engine crossmember and frame differences would likely result in some nasty clearance issues.
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black dawg
1/2 ton status
I suppose shortys would be ok (this thing has huge power down low) just would like to get it to breathe a little better up to 4500. I dont know if this motor is stock cammed or not, but torque feels 500+.
This is for a stockish mud truck (35 inch tire)
This is for a stockish mud truck (35 inch tire)
Bit of info http://www.oldspower.com/vb/showthread.php?t=52736 I just googled 455 chevy truck
MrSchaeferPants
1/2 ton status
Gotta love BBO engines, hope ya find something that works.
meanboyjr
1/2 ton status
Everyone installs a 455 in a GM. Olds is GM
Amen, brutha. AMEN.
If there's one car I miss, it's my old '67 Cutlass.
Anyway, I think a 455 in a K5 would flat out rock.
There was a 74 Cutlass with a 455 olds that would beat the class 8 trucks off the line. Amazimg what 500 lb-ft will do for you.
fabjunkie
1/2 ton status
Big and small block are the same pattern flange wise. The difference is the BB is wider , therefore slightly taller than the SB.
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Doubt anyone ever made headers for a 350 old diesel powered GM pickup,(and I dont think any were put in 4x4's either)--but if they did I bet they would work on a gas olds engine ,at least in a 2wd truck..
I bet a version of some passenger car Olds header will work in a 73-87 pickup,the engine compartment and frame isn't that drastically different than the late 70's full sized Olds were..the 454 chevy chevelle headers I tried in my 77 GMC were "useable",I only put two bolts in to hold them there to see what might interfere,they came very close to hitting the rear shackles on the front spring and the driveshaft barely cleared them also,but probably would have worked..
I just didn't think I wanted them on it bad enough,after seeing they were rusted and would fail soon anyway..I have a hard enough time keeping cast iron manifolds from crumbling into dust here in 5 years..
I bet a version of some passenger car Olds header will work in a 73-87 pickup,the engine compartment and frame isn't that drastically different than the late 70's full sized Olds were..the 454 chevy chevelle headers I tried in my 77 GMC were "useable",I only put two bolts in to hold them there to see what might interfere,they came very close to hitting the rear shackles on the front spring and the driveshaft barely cleared them also,but probably would have worked..
I just didn't think I wanted them on it bad enough,after seeing they were rusted and would fail soon anyway..I have a hard enough time keeping cast iron manifolds from crumbling into dust here in 5 years..
black dawg
1/2 ton status
well, probably gonna just leave manifolds on it. It runs really good, not really needing any extra power.
Agreed,a 455 Olds has probably 500 ft.lbs at 2000 or less rpms in stock trim,you wont need more,and headers might actually reduce the lower end torque some...
Most Olds had a "crossover" pipe from the drivers side manifold to the passenger side one,and then just a single exhaust outlet from the passenger side to the muffler and rest of the system,unless it had dual exhaust factory...might be hard to find factory dual exhaust manifolds nowadays,hope the engine your looking at already has them..or else you'll have to run single exhaust,which isn't that big a deal in the long run--one less muffler and pipes to buy later on...
Most Olds had a "crossover" pipe from the drivers side manifold to the passenger side one,and then just a single exhaust outlet from the passenger side to the muffler and rest of the system,unless it had dual exhaust factory...might be hard to find factory dual exhaust manifolds nowadays,hope the engine your looking at already has them..or else you'll have to run single exhaust,which isn't that big a deal in the long run--one less muffler and pipes to buy later on...
