olds 350 header input

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snotrocket71

Greasemonkey
Feb 20, 2011
218
15
18
Wading River Long Island
hey, i'm sitting in front of the computer with nothing better to do than think if what headers i'd like for my 87. its going to be a stock 350, performer intake, electric fans, non computer hei and carb, mini starter, definetly true duals, 342-373 rear with a 2004r and not much else aside from a good tune on it. i plan on me and my brother splitting it as a daily driver not a race car. i was initially thinking about hedman elite ceramic coated headers, then cheap ceramic flowtechs came to mind, then i thought about shorty headers for ground clearance. do the sanderson O351 ceramic coated headers fit well? would ceramic coating be neccessary? my 71 with uncoated headers wasnt all that bad the only problem was the fact the primaries were pretty well crushed. what about long tubes? i hear all different stories of long tube fitment issues. about how much power would i be leaving on the table with shorties compared to long tubes? i apologize for all the questions and lengthyness, any guidance and experiences would be much appreciated. thank you -Josh R.
 

Oldsmoletick

Royal Smart Person
Sep 18, 2009
1,581
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cny
The only headers I have had dealings with are the standard flowtech and standard hedman (both full length)....My first set of flowtechs, that I had bought 10 years ago, fit just fine, no modifiation necessary. The 2nd, 3rd, and 4th, were not even close, I would have had to cut them apart and reroute one of the primaries to clear the frame :? . I switched to a hedman, and had no issues what so ever with fit, no dimpling, no hammers :lol: . I also like their ball/socket type collector, very nice leak free set up. hedmans were built much better too, material wise.
 

snotrocket71

Greasemonkey
Feb 20, 2011
218
15
18
Wading River Long Island
thanks for the info, i figured the el-cheap-o flowtechs were of low quality. its funny how youre first set worked well then it went to crap, you would think "why change a good thing" but what do i know.
anyone have info on the sanderson or hedman shorty headers (ive heard that they say 68-77 cutlass but still fit later models, any info on that?) the more i think about it the more i think i like the added ground clearance and the fact that its a stock motor with very minor bolt ons so performance wont totally be diminished. even if it'll cost a bit more and i need a custom exhaust bent up its worth it to me. my iuncle has a 11 second (we just put a procharger too so it should be significantly quicker) mustang with BBK shorty headers and a 2.5" flowmaster system that sounds amazing and those dont seem to be holding him back.
 

snotrocket71

Greasemonkey
Feb 20, 2011
218
15
18
Wading River Long Island
the repro w-z manifolds fit small blocks with out interference in a g-body? i have some time before i make a decision, my brothers the one spending the money on the parts and we're both going to do the work so i'm sure he'll want headers of some kind especially since i talked him out of a cam with some backing from members on this site. i guess you could say i was looking at the lesser of a few evils as far as headers. i'm personally a fan of them but if neccessary when the time comes would put the 307 manifolds on it (i have a set off an 85 442) and call it a day but wheres the fun in that.
 

DoubleV

Royal Smart Person
Feb 25, 2011
2,156
406
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Medina Ohio
W/Z manifolds will certainly NOT fit on a small block.
 

DoubleV

Royal Smart Person
Feb 25, 2011
2,156
406
83
Medina Ohio
Blake442 said:

It has been very well documented on this forum and every other Olds forum that the W/Z manifolds will not work on a small block due to clearance issues. The big block engine is taller, so the W/Z manifolds ( which are larger than small block manifolds ) have no clearance issues with anything. Bolt them bigger manifolds to a small block ( which is shorter in height than a big block ) and you'll have clearance issues with the oil filter, starter, and engine mounts. This is why they weren't standard equipment on the W31's.

Anyway, Thornton has created their own version of the W/Z manifolds to fit small blocks. The Thornton ones aren't anywhere near as good as the W/Z's ( not fully chambered because of lack of space/size ), but at least they tried to make something. I have a set ( ported ) and believe they will easily out flow stock SBO manifolds. The whole reason they bothered to make these is because the W/Z's won't fit a small block but they wanted to give us small block guys something better than the stock crap manifolds.

I wish this stuff wasn't true, but unfortunately it is. I would love to run W/Z's on my 350, but it's just an impossibility.
 
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snotrocket71

Greasemonkey
Feb 20, 2011
218
15
18
Wading River Long Island
Thanks for the info on manifolds (both blake442 and DoubleV), i had considered stock manifolds but would like to have the headers for down the road. me and my brother decided that we'll give the hedmans a try because of the larger primaries, cheaper price (im going to see about having them coated locally), and seemingly straight forward install (i doubt it will be painless). I wont be able to post up results for a while because my brothers funding the parts side of the project where as i pay for the storage, insurance and registration side of things and he doesnt have a damned penny saved away for anything. hopefully i'll have a new full time job in the coming weeks (interview this coming tuesday) to help kick start the motor swap. enough of the ranting on my part... thank you all for the info and i'll be certain to let everyone know how the swap went and how well the headers fit or didnt fit. in the mean time i'm sure i'll have a milion and one questions about every imaginable thing i may encounter along the way
 
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