gnasty1521

iTrader: (7)

So I was getting my headers installed and noticed that I have 1 241 head and 1 853 head. Is there anything that could go really wrong with this? I didn't look that close when buying and it runs fine, but I am wondering if the mismatch is causing anything to go bad.

01ssreda4

iTrader: (96)

wow ghetto mechanics

01 BERGER CAMARO SS

iTrader: (77)

damm, a friend of mine did the same thing to his camaro cause he damaged a valve guid on a 241 and it runns but like sh*t...lol..

RevGTO

iTrader: (12)

It's not going to cause anything that you'd ever notice. When was your car built? There was another thread about this from a guy who believed his car came that way from the factory.

They switched from 853's to 241's sometime in middle of MY2000. Your car may have been built that way during the transition.

gnasty1521

iTrader: (7)

wow so it is possible that GM would do this? I was pondering that but didnt believe it. does anyone know the specific differences?

Black02SLPSS

iTrader: (5)

Well other than one head having a perimeter bolt valve cover and the other having a center bolt i dont see much of a problem unless you wanting aftermarket valve covers..

gnasty1521

iTrader: (7)

good call

383lt1impala

iTrader: (33)

241s are perimeter I thought they were center bolt?

BlueBird346

iTrader: (13)

I think they are both center bolt. My 853s are.

nemss1

98 853s are perimeter bolt. 99-mid 00, 853s are center bolt

TireSm0ke

iTrader: (1)

Yes both heads are center bolt. I doubt GM would do that from the factory, although there isnt that much of a difference except for the way they were casted.

outkast6991

iTrader: (34)

wow i didn't know that. 806's are the standard 98 head which are perimeter. all the 853's i've seen have been center bolt.

nprather

iTrader: (15)

correct all 853 heads are center bolt. 806 castings are the perimiter bolt heads

Black02SLPSS

iTrader: (5)

oh, my bad. got my casting numbers mixed up

nemss1

no, my bad. i was misguided

Mike454SS

iTrader: (4)

I've seen cad models for both, including an overlay model of one on top of the other...the only differences in design are strength things (the 241's have some added gussets around some threaded holes that the 853's don't have)...not port or chamber related things...the 853's are not as nice a casting as the 241's though, I believe 853's are sand cast.

My own car is a 2000, and it has 241's...at least the one I can see the casting number on says 241...I'll check the other head with a mirror next time I'm under the hood, I don't think it's an 853 on the other side, but if it is I'll definitely post it up. I wouldn't expect it to make any difference in how it runs, but I'd still try not to mix and match them if I had the choice.

gnasty1521

iTrader: (7)

It just makes me guess things. It is a 48,xxx mile car and I almost went to see the guy I got it from.

s346k

iTrader: (4)

don't worry about it. the car ran fine before, right? i've seen 00 cars 241 heads and my 00 car had 853 heads on it. i think there's a good possibility that gm did it. even if not, the car runs fine, leave it alone.

get some milled/ported afr 205s - problem solved.

LS1Formulation

iTrader: (13)

I have one 853 and one 241 head on my car, CNC ported using the exact same program. There's not much difference between the two.

gnasty1521

iTrader: (7)

sounds like a plan. and yes it does run fine.