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i own gm performance parts crate motor #809-12499529. i have a gm performance intake and an edelbrock performer series 600 cfm carb. my compression ratio is 8.5:1. the heads are 76cc. just wondering if anyone had any good ides on what combinations of parts i should use.
Well I'm by no means a chebbie expert, but I would think the compression ratio is a bit on the low side to get a lot of help from bolt ons. Not sure how much money you want to spend, but maybe some smaller chamber heads, along with the entire Edelbrock Performer RPM package, heads, cam, intake, and carb. Looks like you probably allready have the right carb. If you have to live with the big chamber heads, then a cam change and some headers may help.....
What do you want the motor to do? Did you buy it and then decide that you wanted more power or what? The compression ratio will not support more cam, so be careful, you could make it slower than it is. What's wrong with running it like it is? How much money do you have to spend?Quote:
Originally Posted by 79elcamino
I agree with what has been said. I think a set of Edelbrock aluminum heads and RPM intake would be a good choice, but I do not like their RPM cam as its design makes most of its power in the upper rpm band. A better choice would be a Lunati Voodoo 60102 or 60103, depending what idle quality and performance level you are looking for. These cams are state of the art in cam design right now, and are an improvement over the CompCams XE line according to Harold Brookshire who designed both lines of cams. Just make sure you use the corresponding valve springs for the cam you choose.
With that comp. ratio you will need to look at cams that have a duration @ . 050 of 210 or less on the intake side.Quote:
Originally Posted by 79elcamino
well what id like to do is get an edelbrock rpm airgap intake and a new comp cam camshaft. then the edelbrock performer rpm heads. hopefully getting 9:5.1 comp ratio and running it on regular gas. ive got headers and dual exhaust. but what u really want is what my dyno n my computer is telling me and thats about 410 hp with heads.
Geez, you don't need an RPM intake. I don't understand you guys who think the motor will be faster with a bigger manifold. All you'll do is kill off the low and mid range with it, where you do 99% of your driving. Now, is you're gonna drag race/street drive with a 383 and rev it to 6,500, then yeah, the motor could take advantage of a bigger manifold.
Quote:
Originally Posted by techinspector1
If we are talking heads, cam, carb and associated parts to make 400+ hp, it would seem an RPM intake would be the logical choice. The Performer is designed to make peak torque at 3500 rpm and lose effectiveness after 5500 rpm. That kind of engine is going to see 6000 rpm with peak torque being in the area of 4000 rpm or so. Why would you want to compromise top end? An RPM dual plane manifold is not going to lose that much low end like a Victor Jr. would. I would just like to know the reasoning behind your response, that's all. No offense intended.
What about someting like this?
http://store.summitracing.com/partde...0&autoview=sku
A 400 hp 350 with comp. ratio of 8.5 to 1 can be done but you will have to buy really good heads and a hyd. roller cam.Quote:
Originally Posted by 79elcamino
Put a supercharger on it the comp. is pefect.:3dSMILE:
no ill buy the heads and get 9:5.1 comp ratio
His engine has cast pistons.Quote:
Originally Posted by BigTruckDriver
I don't think I would recommend a supercharger.
No offense taken. You could be right. :)Quote:
Originally Posted by rumrumm
Try this site:
http://www.ryanscarpage.50megs.com/combos1.html
alright i think i know what im gonna do. i think im gonna get an edelbrock dual plane rpm air gap intake, get a 12-234-2 camshaft kit, then get the heads form edelbrock prbably perf. rpm. and in the middle adding high performance ignition wire and a few other things. all i cant decide is whther to push out hte air with a cam kit first or get the intake first? by the end i hope she runs hard.
Dont forget the N.O.S.:D
Quote:
Originally Posted by 79elcamino
Whoa! Whoa, there! Do yourself a huge favor here. Before you order that cam, call CompCams Help line at 800-999-0853 and get a recommendation on a cam that is right for what you want. Have all your vehicle specs with you like transmission, rear end ratio, etc., and let them know what your goal is. They will give you a recommendation on the cam that would work best for you. That 12-234-2 is an XE-256, and it is way, way too small for what you want. You may as well leave the stock cam in given what you will gain. That cam is often used in 283's and mild 327's. You'd be lucky to make 325 hp with it. You'd be much happier with a 12-242-2, the XE-268 which would give you a noticeable idle and make use of the breathing capacity of the aluminum heads and RPM intake, and it would still be street friendly. You want a matched combination of parts in order to achieve what you want. And I can guarantee you that you would be very disappointed with your engine if you use that small cam.
ive run into two problems. one i cant decide whether to get my intake or my cam kit first. two my max hp is 400 but by that time ive reached that my rpms have destroyed my engine. says my dyno. so i need to decrease the slope of my power.
Did you call CompCams? DO NOT do anything until you have talked with one of their techies. Then, report back to us on this forum and let us know what they said. Mistakes cost money and make for a lot of frustration. If you use the right cam and associated parts, you should be able to make all 400 hp and not have to rev over 6000 rpm. Believe me, I've done it.Quote:
Originally Posted by 79elcamino
tehy say i should go with the 12-242-2 cam which is a 268 so ill do that but they still have no idea how to decrease my power increases slope. atleast i got the cam figured out.
So GM recommends red line of 5100rpm on this motor? No wonder you're worried about grenading it. Hard to make power in a 350 below 5000, just can't get enough torque. Does anyone know why GM is so conservative on this? I would think you could spin that SBC close to 7000 at least.... :whacked:
Chris
GM recommends a redline of 5100 rpm because the cam is so small it will not support more than that without valve float. If you change cams and use the appropriate valve springs, you can raise the redline. If you modify this engine correctly with matching parts, you will not have any problems. The recommended operating range for that cam is to 5800 rpm so you are not going to be pushing it much beyond that anyway.
thanks, Lynn...makes sense. Made me wonder how well they build the bottom-end in these new crates....
well i guess since i reach 400hp @ 5000 rpm then i guess i can buy a tach and hold my shifts. that should be ok as long as i dont go over 5000. so anyone got any cheap power upgrades like under $80 to add maybe 5 or 10 horses. need feedbaclk lookin to get as much as possible out of this car.
Cheap power about 10 horses = K&N or similar gauze type air filter = ~$50 don't expect too much seat of the pants difference though for anything less than say 50hp...
Don't know what you're planning for exhaust but much power can be had with properly sized exhaust and good mufflers.
well i want a good dual exhaust kit for my car but i cant find one with mufflers and 2.5" tubing so if u know where help me out. ive got one but its ghetto so i need a new one.