Posted By: GregY
Opinions on cylinder head selection - 04/26/11 12:52 AM
Guys,
I have a '71 Charger with a mild 440. I think my valve seals are shot, so I am looking at options for rebuilding/replacing the heads.
All I want the car to do is go high 12's on the motor, and maybe high 11's with nitrous (if I ever get that far).
How would you recommend I spend my money:
1) Rebuild the 346 heads that are on it now.
2) Buy a pair of reconditioned 452 or 906 heads like Indy Cylinder Heads sells.
3) Aluminum heads (at twice the cost of option 2)
I am leaning toward option 2, but I would like to hear some other opinions.
Thanks.
Greg
Posted By: MLR426
Re: Opinions on cylinder head selection - 04/26/11 01:20 AM
Do a set of 906 heads, the 346 head is terrible.
You will still have to have those Indy heads prepped with a better valve job,runner,valve pocket and port clean up. Then you can think about cam, compression, intake, carb etc. The 71 charger is a heavy car, your going to need more gear also too get that car moving. This project can quickly turn into a money monger, cylinder heads are an important part of making the power you need to run hard, add everything up before jumping in head first. Your budget build can quickly get out of hand to support the time you expect to run.
logan426
Posted By: RapidRobert
Re: Opinions on cylinder head selection - 04/26/11 01:43 AM
Muscle Motors' Steve Dulcich (whose forgotten more info than I know) states that the later heads 452's etc are far easier for the home porter to improve on as opposed to the earlier 906/915 though 452's would need to b thoroughly crack checked & I would get the MP templates & port em (lot of gain/not too much work). Might go to MM archives & read his articles. Been a few reported probs w Indy's stuff but prob no more than the norm (& maybe even less) than any rebuilder as you (most of the time) only get the bad news on stuff here. I ran a set (SB's) of their rebuilt ones & no issues. Iron heads need alot replaced/reworked to get em right but as you said alum ones are $$$ plus need to b checked over after you buy them. Myself in your case w a mild 440 I'd do a bare bones rebuild on your 346's & save for a good set later. dont remem if 346's had hardened seats as they were close to the changeover on that & we know how Ma was on supposed published changeover years
Posted By: JohnRR
Re: Opinions on cylinder head selection - 04/26/11 04:32 PM
The 346 has the same basic intake port as the 452 , flat floor with no short turn.
Greg you are in Rochester NY, contact Dwayne Porter, member fast68plymouth 802 951 1955, he's in Burlington VT. He'll take care of you , best money you'll spend and he may even have a set already to go. Don't waste your time and money on the Aeroheads , you'll just end up with nothing more than a stock rebuild you could get at the local autopart/machine shop for 275 bucks ...
Posted By: gch
Re: Opinions on cylinder head selection - 04/26/11 07:23 PM
OR get a set of 440 source heads and have the valve job checked/corrected.For your goals that will be plenty.
Posted By: AtomicDog
Re: Opinions on cylinder head selection - 04/27/11 12:44 AM
If you plan to keep the car for some time, I'd really consider this option:
http://store.440source.com/Stealth-Aluminum-Cylinder-Head-COMPLETE-SINGLE-HEAD/productinfo/200-1055/You will likely spend a good chunk of $$$ rebuilding the heads you have. Why not purchase something that will help you to meet your goals right out of the box?
Posted By: dem440c
Re: Opinions on cylinder head selection - 04/27/11 07:31 PM
glad you guys already corrected the myths about the 346 - 452 heads. There's been a lot of work done on this, I think even here on Moparts in the Tech Archives are some articles with published tables of flow data showing that in bone stock form there is a slight advantage to the 906 heads, but that all the open chamber heads pretty much even out with port work.
The question in my mind always comes back to whether it makes sense to sink a pile of money into factory iron heads. If you can do your own port work then sure, why not spend your time on that and spend the leftover coin on other goodies. But if you're paying someone else to do the work it gets kinda iffy on which way you come out ahead.
Another note- if your 440 is "mild" you need to be aware of the effect of aluminum heads on combustion chamber behavior before you consider going that route. The rules about compression ratio and fuel type change between iron and aluminum heads
