I have 2 sets of 72 or 73 302 heads I can't remember the head number on them right now but they have 58cc chambers the old 289 usely had 52-54cc chambers. I do know this my dad ran old 289 heads on a 302 with flattop TRW pistons and he was pushing a little over 11 to 1 compression but that was in the good old days of High Octane gass. With my engine set up i will be running in around 10.5 compression but mine will not be a daily driver ether. By the way what part of memphis you at I use to live there several years ago and still have a lot of family there still. Jim
You really won't need much of a cam or converter. With the added compression your low speed torque will be outrageous. Even a small camshaft won't require a converter change. The swap really is an eye-opener. You'll be shocked. The 5.0 engine I used these heads on had a stock camshaft. Car was an '82 GT with a four speed transmission (fourth was overdrive) and stock 3.08 gears. I swapped the heads, a ported Torker 289 intake, 650 holly, and 1 1/2" hooker longtubes into the car. That's all....nothing else. It ran 12.35 right out of the box. :bananaman
heads I live off Getwell near Knight Arnold.it used to be called Indian hills. I;m 2 streets south of american way.
Just for example: Here is a set of GT40 heads with rockers for sale locally here in Houston. Scroll to the bottom of the page for the first post.....their board is bass-ackwards. http://www.westsidemustangs.com/forums/index.php?topic=51137.0 igo1090, "i'm a little confused. you talk about porting the intake & exhaust ports & it will raise comp ratio to 10:1. nothing you do to the ports & passages, or gasket matching for that matter will increase or decrease compression ratio. it only affects the flow of the heads." Where did I say that?????
watch out how much you put in the heads because for as much as i have in my gt40ps i could have gotten a set of aftermarket heads for the same or a little more. new bare casting gt40p heads $257.00 shipped new set of stainless valves $109.00 shipped new erson Valve springs and retaners $136.00 Shipped Mechain work: cut spring pad & bowl hog $40.00 adjust valve spring height $40.00 Mill heads $90.00 $ Grind valves & cut seats $60.00 Carbid porting bit set $72.00 sanding rollers $32 total is $836.00 Plus the head i damaged cost me another $105 so my total was $939.00
Stock on 74 is 8:1 due to 12cc dish and .023 higher deck. Some reports have said this to be closer to 7.8:1 due to manufacturing tolerances being loose. Didn't the 66 289 have 49cc chambers, or some option of the 289 have 49cc?
The stock numbers sound low but you may be right. I'd have to look it up at the shop. The early 289 heads did have 49cc chambers. Not just the hi po units either.
Here is something to think about before sinking a ton of money into older heads. http://www.lonestarstangs.com/forum/showthread.php?t=14195 Set of Dart heads for $600. Mill them and you're in business.
Chiltons sitting right here. 72 and 73 were 8.5:1, 74 was 8:1. I don't remember the later year models for certain, but the 78s had flattops and 69cc heads, I think 8.5:1.
I agree, shop around. Although, I did get to the low 12's with 289 heads 52cc and the chevy valves. A bit of porting and away I went. I just picked up a set of low miles (300) Edelbrock RPM's on EBAY for $830 shipped.. There is frequently heads on there for sale. Don't think I would sink a bunch of money nto cast heads anymore. (the 289 heads mentioned above are avail if anyone is %d)
dear shadowmaster: i wasnt referring to you since you didnt originate the thread. in the 1st posting of the thread yellow72maverick said "if i ported the exhaust side...gasket matched... should come up to say at least 10:1." none of what he mentioned would increase compression ratio: just improve flow.
heads yep thats what I said, I just want to get the most from the 66 heads since I already have them without spending a mint, I just wanted to improve on my 302 heads and make my 72 a bit better on the street. with all this feedback I think I'll do it. I talked to a guy who has been in the head building business for 30 years. I just traded him a 351c 71 block and 2 71 4 barrel bare heads I had in the barn. He is gona hook me up with a good head rebuild new valves springs and all. I think I paid 125 bucks for the block and heads 7 years ago, but he made the deal...
