i have a 84 z28 305 that was rebuilt this summer, in past few weeks i have been in mod madness with adding a mallory hei distributor, edelbrock performer rpm intake, edelbrock 600 carb, and some flowtech headers. the next item on my list is the edelbrock performer rpm cam. it has .488 lift on intake and .510 lift on exhaust. the guy at the local performance shop said they installed one on a stock engine and it ran good. any comments as too is this over camming or will it run good? Thanks.

 

and its too much for a 305. Get a comp cams XE268 or XE262.

 

If you have that kind of lift out of a flat-tappet cam, it must have alot of duration to go with it.

That little 305 probably barely idles if that lift is correct. And if it does idle, it's prob a DOG down low.

Seriously thos specs are massive. Even the XE268 is still very big unless you running alot of compression in that sb.

Stick with a XE256 or if you really want to, an XE262.

The 256 will be a waaaay better driver & much more responsive.

Good Luck.

 

how much lift and duration does the xe262 have? i want to get the most power out of this 305 as i can. low end doesnt really matter as i have a 5 speed and i could launch at any rpm necessary. im not trying to make a grocery getter. i want a car that will compete with ls1 lt1 engines.

 

XE256 is 447" / .454"
The 262 is 462/469 (496/500" w/ 1.6s)

http://www.compcams.com/catalog/056_057.html

your not going to be able to keep up with cars that have 10percent more displacement unless you are turning 10percent more rpm than they are. And thats pretty difficult with a 305.

 

LT1's are high 13 cars.....and most LS1's are very mid 13's & some lower also bone stock. I would consider that.

All i can say is that you have to really spin that 305, and put in a significant more amount of $ than you would have to with something with a larger bore.

I'm sure you've heard this alot of times, but if you want to compete with those cars, get some more cubes, you wont have to RPM that high & your bearings will that you, and it will be a hell of alot more fun to drive IMO.

But to each their own & good luck with whatever decision you make.

 

I second the Comp XE cams. The RPM cam is an ancient design that's grossly inferior to modern ones.

I think your goal is a bit lofty... if your car came with the LG4, you're asking a 145 HP motor with bolt-ons to run against a 320 HP LS1 or a 260 HP LT1. Even with a L69 you're starting out with a 190 HP core. That's not realistic. But, if you had put flat-top pistons in it when it was rebuilt, and a good set of aftermarket heads with some decent flow (NOT the stock ones no matter how much work has been done to them) then with really smart parts selection, including some decent gears and the right cam, you might have a chance with the LT1s. Lightening the car will help. But it's going to be real tough to get a N/A 305 3rd gen to break into the 13s.

 

i am getting conflicting stories here. the guy at the performance shop said it would run good with that cam, and some on here say it would not run good with that much lift and duration. anyone ever tried this cam with a 305, and its not the lg4 305 its a newer one not sure exactly, the lg4 i had, was completely destroyed by a few thrown rods. (giant hole in block) anyways this 305 seems to have a lot more power then the lg4 had, even before the current mods. Im just not sure what advice to take.

 

My friend, i am not going to bash the speed shop owners but here it goes. Around my area, most of the speed shop guys are old muscle car guys who think bigger is better which IS NOT THE CASE IN CAM SELECTION!.

Trust me, the key to a fast performer is combination.

A big fat cam, in a small cube motor(no offense intended) with stock heads, mostly a stock intake & carb and regular gears will not get your car moving.

Listen to US!!!!! DONT OVERCAM IT OR IT WILL RUN WORSE NOT BETTER!

 

I suspect the dealer just wants to sell you that cam. If your car is just for the strip then you can try to go with an XE 262. But if you drive it to work and whatnot you might not like it. Dan Haslett runs one in his 305, which cuts 14 sec flat quarter miles, and he says exactly that.

For your daily driver Comp Cams themselves recommend the XE 256. In fact, there is only a few hp difference between the two, and for my money I'll take driveability over 5 or 10 hp anyday. But with a stick it might be OK.

 

best cams are low duration high lift


this way you can make the big power gains that a high lift cam will give you but you do not get the peaky powerband of a high duration cam, but instead a nice flat powerband still with lots of power

 

only thing is make sure you have a head that can support the cam

you can overcam a head with lift or duration and then slow the velocity of the intake stream down and that is not good


but if you do have to pick between duration or lift
go with lift

 

dont forget too much lift means bigger springs!

 

also if you have the push in type rocker arm studs they may pop out with too much lift

 

I've never seen a small block cam designed for more than .710" lifts, of a big block cam for over .870". I guess anything more than that would be a little too much.