Hello, some of you will remember me. I've been gone awhile. I'm putting my car back together, only this time with a new mission. It used to be my daily driver that I pushed as hard as I could. Now it will be a sometimes driver that'll spend most of its time on the track. I've located and am going to get a 4.10 posi unit, just ordered a new carb and will be servicing my c4 for the time being. What I'm wanting is as much power as I can get out of my current engine. I'll be purchasing a 2600-2800 stall convertor and I'd like to go much larger with my camshaft. I'd like to hear some input from some of you guys on combos and times you're getting with those combos. Thanks a ton! I'll post my engine specs as soon as I can locate them.
Engine specs - 302 bored .040 Flattop Pistons Mild headwork 261 can with .456 lift currently Long tube headers Street dominator Intake Summit racing 600 carb What I'm leaning toward. Come cams 230 @ .050 lift and 512 lift RHS aluminum heads 200 cc intake runne 60 cc exhaust 58 cc combustion chamber 2.02/1.6 valves 2600-2800 rpm stall How does this look to some of you veterans? Any and all input appreciated! Thanks!!
How fast do you want to go exactly? You could always just spray what you already have. Also 200cc runners are really big on a 302. I would look for heads with 165-185 runners, unless you're planning on building a stroker later.
Ha Country; I don't know if you consider a 12.5 ET @ 109+ MPH for a real nice handling and driving 302 ci street car quick. If however, that combination might be something you would be interested in I have a full detail on my Comet (Hot Rock) including a sample time slip in the Garage section of this site. With 3:80 gears and 3500 stall convertor, Hot Rock will go down the highway at 62 mph @ 3000 rpm. Not too distasteful. http://mmb.maverick.to/garage/1972-mercury-comet-2-door.4/ Don't believe everything you read in the car magazines about 400 hp 302 combinations. Those combo's never seem to actually make it into a car with documented track testing and on street performance analysis. BTW, that 2600-2800 stall convertor won't get it! Good luck with your build!!!!!!!
About the converter you don't need to go with a low stall converter if you have a custom converter built for the car I have a 4000 that was built for my 417, by Broader performance! It is as smooth as a stocker driving around the pit' On the starting line it will flash past 4000! I use an off the shelf TCI converter that was supposed to be a 3000 stall it slipped and jerked but it would only flash 2200 on the start line!
Thanks for the welcome! I don't have a set goal in mind really, because I don't have a baseline. I'd love to run 12's, but I don't really know what I can expect out of my current combo. And then I don't know what sort of gains to be looking for. When I was younger, I street raced a lot. I know what the current conbo would run with, but I don't know what the track numbers would have been. It was a LONG hike to a track. I don't want to do that anymore. When I turn loose it'll be on a track. I do want to have a quick car that I can enjoy a cruise to turn a few heads every once in a while. I just need help with the roadmap to get there. Thanks for any and all help! And the advice so far!!
I am probably going to go with a stroker for my next one... So I was thinking I would go with the bigger heads now... Will it hamper me now?
I am far from an expert on the subject, but using heads with too large an intake runner your throttle response is going to be lazy, and will hurt torque.
I agree and generally speaking.. Dan is right about matching port size to the intended application. but that older "port size rule" comes much more into play when using factory stock parts or lower cost entry level heads(with entry level port designs). The newest head designs just do so damned well across nearly all lift ranges these days that you don't need to entirely recam and regear for optimum results like you used to. So with that said, there are no hard rules set in stone when it comes to port volumes. Aside from the camshaft, the actual cross sectional size and shape of the port itself, not to mention valve size and their inclination angles over the cylinder, is what basically controls the ports overall velocity profile in a running engine trying to accelerate at WOT. But just like the carb discussions often go.. actual race weight, gear ratios, compression ratio, camshaft design(<-- controls your running dynamic compression ratio/DCR).. etc, etc.. ALL impacts the final optimum intake port sizing requirement. Light cruising around town with too big a carb, too big a cam, too big a intake manifold, and finishing it off with too big an intake port leads to a lazy feeling engine with poor transient throttle response below 3,000 rpm. Unless of course you wanna start running around town with 5,000 stall and shorter 4.62 rear gear to make that combo work?.. your pretty much just screwed yourself out of a civil and well rounded street engine. I would sum it up like this. It's always best to pick the head for the intended power level you hope to REALISTICALLY achieve rather than picking a head that flows xxx amount of air @ xxx number of cc's. Tons of other guys around here and out in 5.0 land running these parts so your work's already well cut out for you. Let's say some guy in one of those cookie cutter stroked "pick a year" 5.0 Mustangs is making 650 full race horsepower @ 7,500 rpm using AFR 225's?.. why should/would you buy them to fit your simple little 10:1 compression 302 spinning only 6,500 rpm? It's all just an airflow recipe to better maximize inertial tuning within a more specific range of engine speeds. Get it right and the motor will overachieve almost every place in the power band and that'll keep you happier in the long run. Typically the smaller volume heads are good for those guys who plan on either staying near stock displacement and probably not intending to rev the living snot out of it, maybe some mild strokers with slightly lower "pump gas" compression ratios, and/or those who just want gobs or low end grunt in trade for a few less horsepower on top. Those guys don't buy really big cams for those combo's anyways, so they don't need the huge airflow capability of the biggest heads. Personally speaking, I typically always overspec' by about one size up the port flow/size chart.. or more preferably, buy modestly sized ports based on the mid-range power requirement and then port them to extend their rpm capability. It's been proven time and time again that smaller ports which have been worked on and refined to a greater degree can easily beat out the larger as-cast versions of the same exact head casting. This is because the velocity profile and flow around the valves head(curtain area) have been improved everywhere in the valves lift range which improves the engines entire rpm band. An AFR or Trickflow head around 180-190cc's will easily make over 500 horses. And far far more with good porting. PS. Here's some info from some dude way smarter about cylinder head theory and practice than I'll ever be in this lifetime. http://www.dartheads.com/tech-articles/port-volumes/
Robs right,go w/ AFR 185s & I would try the Anderson 91 cam,several guys on here like that cam a lot & don`t go bigger than a 750 carb.
