Vega

Okay, id like to know the pros and cons of Ga heads. Im still looking into rebuilding my olds 455 and i have a set of Ga heads lying around that i want to use. From the research ive done they honestly dont seem to be that different from Cs (not enough to make me want to go spend the money on another set of 40 year old iron heads in need of a rebuild anyway) and in fact ive heard of a few advantages that Ga had from the factory. So can someone list the pros and cons of these heads please?

Also is there anyone out there who has built a set of Ga heads for performance? This wouldnt be a daily driver (obviously, who the f#ck can afford to drive a big-block daily these days anyway?) but more of a street-rod built for reliable power.

*Oh btw, 95% sure these are small-valve Ga heads, they came off a non-drilled crank motor (Olds...why...whhyyy...seriously, why?)

cutlassefi

Nothing wrong with the Ga's imo. Put big valve in them, clean em up, and you're good to go.

Vega

Thats what ive been thinking too, if im going to spend any more money on heads im gonna go big or go home with Edelbrocks, just i dont have $1500 to shell out on heads right now haha. Was just kinda wondering what the details were on Gas cause i cant find anything on them anywhere but it seems like theyre getting quite popular now that the Cs are thinning out. Also if anyone could tell me how far Gas and/or any stock iron head could be milled down safely and streetably would be very convenient. Id like to get them down to 77-75cc

cutlassefi

Normally 75cc wouldn't be a problem but it also depends on how much the chambers have been smoothed etc. Not sure why you need to mill them that much though, you can get close to 11.0:1 with an SRP piston and 0 deck.
All big block heads are similar in flow except the J's and that's because of their exhaust humps and small valve throats.

Weld the center divider, fill the crossover and with a little bowl work you'll have a pretty decent set of heads.

Vega

thanks! I'll be trying that. Also the milling was a future plan for a more...extreme style build...of around 13:1 hahaha, i'll leave the specifics out because it tends to stirr up a hornet's nest, especially here on the internet where propaganda flies like confetti lol.

As far as my current situation of shooting for a low-mid 10:1 compression, would it be cheaper to mill the heads? or deck the block? Ive got to get both worked on anyways, heads need completely rebuilt, most likely replacing everything, block needs cleaned, checked, and prepped. Just looking for the cheapest way to hit 10.5:1 or maybe a little lower to run premium

PS: I noticed your EFI set up, may i ask what youre running? and would it work on a 455?

cutlassefi

Accel Gen 7. Yes it will work on anything from a Quad IV to a Monster Big Block.

Run to Rund

I have run GA heads and they were fine. The intake port roof is a little lower, to accommodate the taller valve spring installed height. Flow didn't seem to suffer, though, and the taller spring height is a real plus, about .2" more, in finding good springs for some camshaft requirements. The "ramps" in the floors of the ports near the valves, especially intakes, allow hardened pressed-in seats but also help flow.

If you have big valve GA heads, they already have pressed in exhaust seats from the factory. If you have the small 2" intake valves, they don't, and the exhausts may be the 1.68" with 30 deg. seats (instead of 1.63" with 45 deg. seats). Your shop should be able to change the valve sizes, iirc, and machine new seats. Or, just use what is in them--not a big issue for mild to moderate builds.

Vega

Thanks for the advice! Yeah this pretty much just re-enforces my original plan to just build a performance-minded street motor on my Ga heads. Valve job shouldnt be a big deal since they have a planned rebuild anyways. All i need now is to find someone who's knowledgeable in Olds in the Indiana area.

As for the EFI, i'll definatly be looking into that

507OLDS

The Ga's will work just fine.Put a 2.07" intake valve in it,and leave the exhaust valve the way it is.No need to make it bigger.

67 Cutlass Freak

I think the Ga heads should be fine for what your trying to do here. Deffinately go with the big valves. If your going to run the stock exhaust manifolds don't bother with welding up the dividers unless your planning on switching to headers. You should be careful about milling the heads or deck too far or you may run into port alignment issues with your intake. It would be wiser to pick up the right pistons for the 10.5:1 compression your after. Here's a thread that talks about porting where I showed some Ga's ported against some early SB non ported heads.

https://classicoldsmobile.com/forums...strip-use.html

Vega

Thanks for the info, i'll definatly look into this