hey all.. cant afford $650 for S/R torquer heads for the 305. I just took off the heads and took them to a head specialist to have them rebuilt and what not. They dont port or polish or anything like that. i know everyone says these heads are worth jack, but if i have my own porting kit, would it help a little if i do some mild work on them before putting them back on???

also, is there a Tech article WITH PICS(yes i used search to no avail) that you guys know of? i should have my heads back on wednesday. The mods i have are in my sig. less the upgraded Cam thats in there. i dont know what kind it is, but i know its NOT STOCK!!. anyone with info would kick *** thanks

 

Actually, the heads I took off my LG4 are 416s, which are supposedly pretty good if you're gonna port the hell out of them. They're supposed to flow really well.

 

The 416 heads have lots of potential.
You need to port them thouroughly and upgrade to 1.94x1.60
valves.
A little porting will only get you a little more power.
Don't be shy here.
There are many threads on porting these heads.
You couldn't have looked that hard 'cause.......
I port them up to good effect getting between 225 to 234 cfm
@28" on the flow bench.

Get a book on modifying cylinder heads by David Vizard
everything in there about hi perf heads and porting is relevent to the 305 heads.

Don't waste your time with the stock 1.84" valve.

 

I feel your pain

But I also have your salvation! Go the link at the bottom of my sig and behold what you have been seeking!

 

Thanks for the book info F-bird'88 I will look that up at the book store tomorrow. They can order it.
I have a set of 416's that I bought from Peformance Chevy in AZ that already had the larger valves and screw in studs installed. I plan to port them a little bit more for using on a 350. I started falling into the trap of listening to other tell me I needed better heads. My brother keeps telling me I can get some decent numbers with these heads.

 

do all lg4's have the 416 casting, cause i want to port the heads of my parts car, and it is an 86 lg4 car.

 

Most likely. The 081 centerbolts heads will port up nicely too.

All small chamber heads but the *swirl port* heads have good potential once you increase the valve size and open them up some.

 

FWIW, the instructions in the Standard Abrasives Deluxe Porting Kit (which essentially says the same things the above mentioned book says to do, and don't cost you anything - I printed them out from their website before I got the kit to study before I started) use a 305 head in their illustrations.

I agree with the 1.94" valve recommendation, and would further recommend conversion to screw-in rocker studs, reducing the guide height for more clearance b/t guide & retainer w/higher lift cam, and upgraded valve springs.

None of this will do you much good if you don't upgrade the cam and install headers (+ full high-flow exhaust) while you're at it.

Also, FWIW, it is possible to go "too far" while porting. Stick with the guidelines and avoid the "bigger is always better" trap.