yes, another hp/torque estimation thread

[aldeswarii]

anyway, just wondering what kind of numbers you think this setup would produce in a 68 coupe

302 bored .030 over

mac long tube headers
dual exhaust, h-pipe, turbo mufflers
stock heads from a 289 (were the 302 heads any different from 289 heads?)
edelbrock performer intake, cam and lifters.
600 cfm edelbrock carb.

did i forget anything? three in the morning, tired as hell

 

[Ronstang]

Not much....those heads kill the deal. You need to think about some real heads.

 

[aldeswarii]

yeah i know the heads aren't the best (probably the worst haha) but for now i'm not looking to make a beast

 

[Ronstang]

I think 200HP at the wheels would be about the most.....and that is optimistic considering a stock 289 only puts about 125-50 on a good day depending upon configuration. Mustang Monthly did a dyno shoot out of stock cars a few years back and even HiPo 271 HP cars were abyssmal and at around 150 HP to the wheels. You have to remember that these engines were tested for ratings with NO accessories and NO water pump on the dyno which is completely ridiculous.

 

[aldeswarii]

hmm, well what heads would you suggest?

 

[Ronstang]

The heads I would suggest depend upon your budget. If cash is tight and your goals ae mild then a used set of iron GT-40s would be real nice or you could look for a set of good used aluminum heads. If you don't have a specific performance goal or HP target and just want a good all around street car then I suggest you pick up whatever aftermarket head you can find used that fits your budget because all of them will be significantly better than stock.

 

[Stang_1973]

I have heard that the GT-40 heads can make a significant difference. Make sure that they are not GT-40P heads because these supposedly arent very good. try searching ebay, Gt-40 heads run between $400-$600.

If you want some real performance get some AFR 165 series, they should work well with your setup. I have heard AFR does wonders with their heads. Oh yeah, trick flow, twisted wedge heads are supposed to be real good too. both of these are upwards of $1000 new.

 

[ratio411]

I am not going to argue much that aftermarket heads are way beyond stock heads...
BUT:
Folks around here don't give stock heads enough credit either.
My 306 Maverick did low 8s @ 80 something mph in the eighth... (it was 12 years ago)
The heads were modified stock, the gears 3.00, 60' was high 2s, and traction was nil. The car was faster than my Z. The Z pulled 318/334 at the wheels. Not bad for 68 SBF heads on a 78 block.
The funny thing is, back then there were even faster cars with stock type heads.
I just wanted to rant a little over everyone dropping in on threads and instantly dismissing stock heads when maybe that is all the person has to work with. It would be another story if they discribed a way to make the stock heads better, then put a side note that aftermarket heads have more potential if you can afford them.
Done
Dave

 

[Ronstang]

I usually dismiss stock heads for the kind of people that have to ask what parts they need to make a good engine because these folks probably don't have the tools or the knowhow to modify stock heads to perform well and by the time they spend all the money on porting and new valves and springs they are in the price range for used aftermarket heads easily. It is a matter of economics. My Shelby has the stock heads but they are modified with 1.90/1.60 valves and a port job and the car runs 13 flat with no problems but I could bolt on aftermarket heads out of the box and make more power but I won't for obvious reasons.

 

[ratio411]

...the car runs 13 flat with no problems...

That's what I'm talkin bout!
I had late 289 heads with 1.94/1.60 and mild port work, they really screamed...
Budget constraints of being a teen then kept me stock, today my kids eat me out of house and home, so I would probably go that way again. Though I would like to try 351w heads.
Dave

 

[Ronstang]

But Dave......the Shelby also has a $2500 set of Webbers sitting on top of those ported and revalved heads along with a newer mechanical cam, a stall converter, a 3.89 geared trac-loc.....blah blah blah.....it isn't going to run that good with a 4 bbl and a 3.00 peg leg. I didn't change the heads because they are original and belong on the Shelby and the mods are invisible. The chambers are 49cc so I am at about 10.5 compression or higher on iron heads and no pinging on pump gas thanks to the Webbers....no 4 bbl is going to do that.

The point is that that level of performance on mostly original equipment (castings) is not cheap or easy to obtain. If you dropped off a set of 289 heads at a machine shop and told them to port them, put big valves and seats in them, and put all new springs and retainers on them you will be into those heads for at least $600 probably more and for that kind of money you can have aftermarket used heads these days. Even older aftermarket heads are better out of the box than my reworked 289 HiPo heads....PERIOD.

I'm never said you could not get decent power out of stock heads, it just isn't going to be earth shattering. Most people don't have the skills or the tools to rework the heads themselves and most home port jobs by people just getting into cars end up with junk for heads.....this is why I try to steer people to spend their money where it will do the most good.

 

[ratio411]

But Dave......the Shelby also has a $2500 set of Webbers sitting on top of those ported and revalved heads along with a newer mechanical cam, a stall converter, a 3.89 geared trac-loc.....blah blah blah.....it isn't going to run that good with a 4 bbl and a 3.00 peg leg. I didn't change the heads because they are original and belong on the Shelby and the mods are invisible. The chambers are 49cc so I am at about 10.5 compression or higher on iron heads and no pinging on pump gas thanks to the Webbers....no 4 bbl is going to do that.

I must have had a freak then...
I was only able to use 2 of my 4 gears in the 1/8, I crossed the traps at close to 7k rpm at 88 mph.
I tried to get it into 3rd before the traps a couple times, but I would end up putting in at too low an rpm to get improvements. I did best letting the valves float for a split second as I crossed the traps in 2nd.
Stock heads, 750 dp, 228/235 cam, 3.00 gears...
I never got back to the track after 4.11s. It felt much faster when I could get any traction. The biggest improvement is that there was no bog off idle, the 3.00s forced me to smoke the tires or the car would fall flat on it's face.
It sounds like you have a ton of dough in your car, but that isn't always the answer.
Good discussion...