Okay, so I'm porting my heads and I'm going to have to make some modifications to the deck surface and get the heads milled. I got a quote of $50-55 to do the heads for a standard milling, but it's a bit more (didn't ask on price) to do angle milling. I wasn't even considering angle milling, so I didn't bother.

Anyways I asked on a valve job just to get the seats and valves cut and he said $275 no matter what size valve I have. Its a 3-angle cut and they use a 78* bowl cutter. Now, if I end up getting a valve job, I'll probably go to 2.00/1.55 valves just for the heck of it.

However, I'd like to not spend that $275 and keep my current valve sizes. The valve seats look fine to me, no abnormal wear or marks, and the valves even look good too.

More than likely, I'll be buying some shiny under-cut valves to put on these heads (1.94/1.5 stock) to help improve flow a bit more, but I don't really want to spend $275 on a valve job if I don't have to.

Can I use new undercut valves on my current seats if there isn't anything wrong with them, or do I need to get the seats machined for undercut valves? If I need to get them machined anyways, I'll just say screw it and stick with the stock valves.

 

What heads are you using? Squeezing 2.00-1.55 valves into a 305 chamber can be tricky. Although those valves (and even larger) can be made to physically fit the chambers and clear the perimeters, there is reduced flow around the outer edges of the valves as size increases. With a 305, clearance must be provided to unshroud the valve perimeters, and this necessarily increases the chamber size, reducing compression. It may be better to increase cam lobe ramp and lift to improve flow in that engine, rather than increasing valve sizes.

 

Actually I'm just going to stick with the 1.94/1.5s that came on these. I'm going to use modified aluminum LT1 heads (using LT1 intake as well). I think I may just stick with the old valves for now as well. I'll replace them if/when I switch to a 350 and at that time I'll get larger valves and a nice 3-angle valve job.

I'm going to use a Crane Compucam (2031) with 208/218 durations and .438/.458 lift. A bit weak in my opinion, especially on the lift, but that's what I have easy access to. I'll just use the stock LT1 springs then as well until the 350 swap..

 

Since they're going on a 305, you might want to stick with your existing 1.94 intake, but it may be nice to go with a 1.55 or even a 1.6 exhaust valve.

Yeah, that cam's lift is a little mild, but you can also use 1.6 rockers and get a little more.

 

I don't know if you even have to worry about the exhaust either. I don't have flow numbers on the stock LT-1 heads, but aluminum L98 heads flow VERY WELL on the exhaust and I'd suspect the LT-1 heads do too.

The exhaust of the aluminum L98 heads out flow many of the aftermarket heads due to the efficient design of the D port. In fact, when it comes to porting, most guys just clean up the exhaust and concentrate solely on the intakes

 

The stock numbers are quite impressive. IIRC, they are a bit better than the aluminum L98 heads even. Supposedly someone got them to 265/190 with home porting and stock valves. I'm not going to get them flow-tested I don't think, but I doubt they'll be near those numbers. I'd assume a bit better than stock though, I haven't really screwed anything up yet on the one head I finished (well almost, just need to pollish the exhaust now), lol

They should flow nicely for a 305 I really didn't have to port them. I only decided to so I could get some practice and say I had ported/pollished my own heads If I had all the stuff to do the swap on my car already, I wouldn't have bothered, but I figure its going to take me a few months to get the rest of the odds and ends (gaskets, hoses, machinework, etc.) so I might as well make some use of the time. I have nothing else to do to my car right now