i did some research on my lg4 and found that my stock cam's lift is at 234/257. so i bought a new comp cam kit that comes with cam springs timing chain set and the small things to go with the springs. didnt come with the pushrods or rocker arms. the new cam is 464/470. thats a +230/213 difference. my question to you is this. will that clear my stock pistons or do i need to change them too? also will my stock 1.5 ratio rocker arms work or should i get 1.6? if i need to change anything else like pistons or rocker arms im gonna have to hold off till i get them. thanks for letting me know.

 

First off, the specs for your original cam are lobe lift and the replacement cam are for valve lift so you arent gaining as much as you think. Next you should worry about blowing out the valve stem seals as stock heads are very close if not over your valve lift. The valves will clear the pistons as long as the cam is installed properly.

 

thats alot of lift for an LG4 why are you going with such a big new cam ?

did you port the heads, install larger valves and exhaust?

anything else ?

plan on running high RPM often ?

interesting...


i wouldnt run really anything more than a stock 350 replacement cam in a little LG4

but thats just me.,

ive put in camshafts into quite a few SBC's over the years
the most recent was a couple months ago in the 85 elky we are completely retoring and have newly painted recently,
the stock original LG4 in it i totally disassembled and sent to the machine shop
it had to be bored .030 to save its life, and the crank journals all had to be turned .010 under, it had over 200k original miles it was tired and smoking

i put in a stock 350 replacement cam and it runs STRONG very happy with it and with the crappy 2.73 axle it hauls ***** VERy well



good luck!

 

yes i do plan on porting and polishing the heads and installing larger valves that or im going to get new heads which ever is cheaper. so far this is what ive done. new (well used) 600 cfm holley on top of a new edelbrok performer intake, new vacuum advance hei dist and a set of hooker super comp headers yet to be installed with the y pipe. waiting to get hi flow cat and the rest of the exhaust from the cat back. thinking about going with a borla muffler too. and yes as soon as i get my hands on a 350 all these parts will be swapped over for sure. anyone know the stock duration on the lg4 cam i couldnt find it anywhere

 

so i found these http://store.summitracing.com/partde...5&autoview=sku think that'll help eh

 

To answer your question, yes it will clear the pistons fine. Bout the same lift I'm running on mine and I've had it up to 6grand on a fairly regular basis and haven't broken a valve spring yet

 

I wouldn't put those Summit heads on a 305. 67cc vs. 58cc stock chambers, you're going to lose a bunch of compression. 2.02/1.60" valves are overkill. They'd be fine on a 350, though.

 

i wouldnt run those heads near a 305, they have 67cc comb chambers