chevy guys need help

[slow90lx]

We have inherited a 1979 GMC Sierra Classic but the motor needs to be rebuilt. It has a 305 in there and I'm leaving it in there since this will be my sons truck when he turns 16. I'm doing a stock rebuild but he would like it to have a nice cam because of the sound they make. So here is what I need, what cam can I out in this thing that will sound great? Not worried about lots of power gain.

[holeshot]

Comp 272 Adv Duration, 454 Lift .
It will sound good and pull fine with the 308 gears that are usually in those trucks.
Good luck .

[fastwhite99gt]

Look into the thumpr series of cams from Comp Cams, give a very nice sound without killing the low end.

[stevo]

Comp 272 Adv Duration, 454 Lift .
It will sound good and pull fine with the 308 gears that are usually in those trucks.
Good luck .

Will that work with the stock-type springs?

Stevo

[junk racing]

i would change the valve springs no matter what you do, they are a wear item

[holeshot]

Stevo: yes it will work fine with stock springs.
I do recommend new springs though.
Z28 springs are cheap, like 30 bucks.
And are easy to install.

[slow55]

Way back in the day I used to use the comp 280 cams in stock motors.
The will work with stock springs, rockers and will idle around 800 rpm and hit pretty damn good. They work fine with a stock converter but if use one that stalls about 200 to 400 more than stock it works even better

[Magnimike1]

Stevo: yes it will work fine with stock springs.
I do recommend new springs though.
Z28 springs are cheap, like 30 bucks.
And are easy to install.

and an Xe268

[holeshot]

Oh ! If you go above 480 lift with rotators retainers on the exhaust valves its very possible it will coil bind and break springs our rocker arms.

[Jimbo]

Summit has a few cam and lifter sets for $100 that would work well. The part numbers start at SUM-K1100 and go up numerically depending on the aggressiveness of the grind. SUM-K1103 would be decent in your 305:

http://www.summitracing.com/parts/SUM-K1103/

[stevo]

Yeah, that is why I said stock-type springs, I wasn't trying to imply the old springs, just stock replacement springs.

Oh ! If you go above 480 lift with rotators retainers on the exhaust valves its very possible it will coil bind and break springs our rocker arms.

That is the number I was looking for, thanks.

Stevo

[slow55]

Yeah, that is why I said stock-type springs, I wasn't trying to imply the old springs, just stock replacement springs.



That is the number I was looking for, thanks.

Stevo

Comp 280 then. something like 235 duration @ .050 and 480 lift.
Works good and sounds great

[gspfunk]

Honestly, if he just wants it for the sound, just bump the idle down 100-150 rpm. If ya'll are doing it for the experience of building it together, then go w/ one of the ones listed.