dont feel like putting alot of money into the 305 since im just going to build a bigger engine as the money starts to come in...but i would like more performance for the summer. So im curious as to what heads can i get that will flow good on my carbed 305? Im thinking maybe some stock 350 heads, get them ported and polished and then have them so i get a better compression ratio at one go. Any idea on heads i could do that to? My new engine will have afr heads, but i dont have that kind of money or anything like that, kinda looking for something to give me a good power boost since cam and intake...ect will be done before summer is in full swing. Thanks for any ideas guys!

 

Follow the link at the end of my sig

 

Not sure how you figure that. 350 heads on a 305 will worsen compression ratio, especially if your 305 is an LG4 from '82-'84 (would have been nice if you said exactly what you've got).

Most likely you've got the best 305 heads on there already. Doing the porting and polishing as Bull is suggesting, along with better valve springs, and better cam, and better exhaust, and (if LG4) better air cleaner, you can expect better power.

Just porting heads, especially 350 heads, won't get you there.

 

the only reason i refered to stock 350 heads is i figured they would flow much better then 305 heads, then after some port and valve work have them decked so i can get a CR of around 9:1 or somthing. Think vette heads used the same size Cumbustion Chamber as the 305 heads did. After looking at the 305 port guide i figured it would be fine with some 305 heads and decent port work. What are the casting numbers for the best 305 heads? figured it might be the Tpi 305 heads or the H.O. 5.0 heads. ohh...it's a LG4 by the way and too slow right now. Will the TPI heads even work, or do they have a different bolt patteren then the LG4 heads? not sure on that.
Thanks.

 

The LG4 heads you have should be 416's, which are the best 305 heads!

 

Yes, the vette heads had 58cc chambers just like the 305 heads. If your engine is a 305 built up to and including 1986, you will want either 416 or 601 heads. (It is what was used on carbed and TPI engines.) If it is a 1987 model you will want 081 castings.

It is really important to get the intake valves opened up to 1.94" from the original 1.84".

Headers will make a WORLD of difference to the old LG4, too

 

thanks for the info. i might see if i can get a set of 416's cheap and send them away for the porting and valve jobs. What about the exhaust valves? should i get bigger ones too, im think of getting the undercut valves to maybe get a few more hp out of it. Wouldnt the vette heads flow alot better stock since they were designed for a 350? maybe if i can score a set of those and get all the work done i would have alot better flow then a fully worked on 305 head...or would it make that much of a difference to even bother? I plan on building up the 305 in a budget sort of way, but when i build the new engine im going all out (reason im on a budget for the 305, dont need to spend to much money on a engine that i dont expect to be a huge power house, next engine will make around 500 hp ) All in all, i hope to hit around mid 14's this summer...which will be alot better then the 16's or so i should be hitting right now.
Thanks

 

Read through the link I posted at the end of my sig. It answers most of your questions. The L98 350 heads are essentially the same as the 305 heads, except they are already sporting 1.94" intake valves. Some folks like to open the exhaust to 1.60". Do the porting and polishing yourself--that is how you save big $$$ in this swap! The heads will flow like Vortecs or better

Mid-14s are quite doable.