combo
 

i have a set of 188 cylinder heads, and would like to know if these heads are just as good as the 990's. i also have a 1971 454 4 bolt block. what are pro's and con's of this combo. what would be a good gt combo for a 78 malibu! thanks for the advice.

Re: combo
 

188's like came on GenV 502 if so use them.From my experience they are better than 990's.The ones I've worked with did better than typical 990 I've done them port matched&bowl blened to max ported and numbers on flow bench both ways were better than 990's low lift all the way through high lifts were better on 188's than 990's.
Only problem I've seen is exhaust guides crack and leak water into valve guide which
new valve guides fix that If you are having guides replaced make sure person doing it knows exhaust guides have to be removed on GenV heads by driving them out towards combustion chamber that is from valve spring side down towards combustion chamber
the older Mark IV heads exhaust guides have to be removed the opposite direction.The exhaust guides have steps on them is why they have to be removed a certain direction or it will ruin the head. S.I. valves have Gen V bronze exhaust guides only source I found.
Mike Taylor 3601
You have to use certain head gasket if use on Mark IV block I can't remember fel pro part# without looking it up.

Re: combo
 

Thank you sir for your response, the heads that i have are 1971 casting's and i have a 1971 block. i was wondering if this combo could be competitive in superstock in a 78 malibu in one of the gt class and which class would it fit into?

Re: combo
 

Thank you sir for your response, the heads that i have are 1971 casting's and i have a 1971 block. i was wondering if this combo could be competitive in superstock in a 78 malibu in one of the gt classes and which class would it fit into?

Re: combo
 

I might have goofed on casting #. I can't tell you for sure about that combo in S/S but I can tell you how to look it up if you don't know. Go to blueprint specs on NHRA site you can find the specs for your combo if you have 71 heads start there and find your casting # head those heads could be used on different combos,w/ different HP ratings,might be used on several size,several years,you'll just have to research it.Gather up all your info and compare all the different combos if there are several and decide which one is the best combination. Myself I have stockers one 305 chevy & the other 229 chevy (305 minus 2 holes)I like these combos because cores are cheap I have bought heads as cheap as 10 bucks a piece I have big stash of heads, intakes& blocks for my combos without many$$$invested.Do you know what your talking about when considering S/S I'm not trying to discourage you or crush dreams,S/S takes alot of $$$. just making sure you know whats involved before you jump in.
Mike Taylor 3601