Hey guys I am starting a build up on a 430 for a 67buick GS340 I want to get some head work I am having a local shop do the valve work, but i wanted to do the port work myself. Mainly because I am a college student and money is tight. I would send the heads to Jim at P.A.E but I live in Ohio so shipping would be outrageous. So i think I am going to do it myself. I have heard that polishing the combustion chamber is good and also porting and gasket matching the ports. This engine is going to go in a street car that I will take to the track once in a while. I am searching for about 400 horse power. I plan on using the B4B intake with a GS 116 cam ( I think) plus the poston headers. Will this set up get me to around 400 horse? The heads are from a 69 430 I need to know what the best modifications for these heads are I really don't want to swap to stage one valves and then how to do them. More specfically how do I polish the combustion chambers. Thanks For your imput thanks Adam
I can say from experiance that smoothing the chambers is well worth the time. I had all kinds of pinging trouble with mine until I did that, As far as stock heads I understand the 67 and some 68 430s had a big port head that had a better intake port than the other heads but I understand its hard to find these heads that are not cracked. Tom
Adam, polishing the chamber will jelp reduce detonation. Doing a gasket march without doing any bowl work is pretty much a waste of time. I'm not saying don't do it, but make sure you spend some time in the bowls, that's where the flow is at. Getting 400 horsepower form a 455 is pretty easy to do. Jim Burek
Adam Your engine setup sounds just like mine. Mine is a 455 with 70 heads, a B4B, Poston GS116 cam, and I have an old set of KB headers and a Quadra Jet. Torque will be a big problem, you'll need good rear suspension and good tires. My car weighs 4030 with a half tank of gas and has gone as fast as 13.51 in the quarter mile, although it normally runs in the 13.60s. If the power formulas are correct that means around 390 HP. If I was doing it again I wouldn't use that cam, cause I don't think it's a lot of improvement over stock. Heck I'm shifting at 4300 RPMs to get my best times, course it ought to last forever at those engine speeds. Good luck!! Dave Berry :TU:
Ok guys thanks for the info The motor is a 68 430 not the 455 sorry i didn't state that I don't understand what the bowls are and what do you do to them to increase flow. what method do i use to smooth out the combustion chambers. does my combo sound pretty good I.E cam, and intake choice. thanks Adam
Very little difference horsepower wise between 455 and 430, but think your not thinking quite enough cam. Dave Berry
I used an electric die grinder with those sanding rolls when I did my heads. But you have to be very careful because it is very easy for it to catch a edge and ruin the valve seat or head gasket surface so if you do any grinding/polishing do it first before having any other work done. When I did my chambers I stuck a couple of junk valves in the guides so I wouldn't wreck a valve seat since they already had stage1 valves installed. Tom
The "bowl" is the area under the valve, when the head is upside-down (chamber up) on your bench. Like the bowl of a smoker's pipe... Smoothing out chambers is just that, using a die grinder to get rid of any sharp places that would keep heat and cause detonation, plus polishing the surfaces to make it hard for carbon to build up and also cause detonation.
thanks What grit do I use to do the chambers. I thought I heard one time that for port work to go done to an 80 grit but this is proballyto much for cleaning up the chambers Also what needs to be done to the bowls just smoothing them out to or what. You guys are a great help thank you very much thanks Adam
I'm pretty sure that Standard Abrasives DIY guide will answer those questions, or there are several threads here that will. Do a search on "porting heads bowl", you'll get tons of info with pics.
I did the heads on my car last winter, and found that a dremmel tool with the flex extension,with the drums, makes for a nice finish.
