Rebuilding

[AC_DC_2001]

Well, here's where I'm at so far. I have completely disassembled my 350, all but cam bearings. Since then, I have been fortunate enough that my uncle had a 305 out of an 84 camaro that blew up when a boy that was racing it was going 110 mph. The 305 had 2 thrown rods, and busted the cam in two. Now, I stripped the motor for him before he sent it off for scrap. I have the heads, which were rebuilt one month before the motor blew up. From what I can tell they are still in excellent shape, when I pulled the valves. I could still see that the seats had hardly any wear, but the seals had dried out from sitting without oil, and the guides look to be in good shape.

Now, here's the thing, the reason the motor threw a rod was because of improper torque on the rod cap nuts. I checked the piston heads that were thrown and saw that they had marks where they hit the valves, but I have checked these valves and they show no signs of chipping or cracks. I want to try and put these heads on my engine. I'm going to go ahead and play it safe by reseating them. I have to put a new cam and lifter set in my motor because my cam has very bad heat marks, pits, and chiped areas all over the lobes.

Is it a good idea to put these 305 heads on my 350, or should try to salvage mine? Mine aren't in bad shape but, it will take more to fix them than it will to fix the 305s.

Robert

 

[78subgeorge]

Compare the size of the combustion chambers. If they are considerably smaller, the compression ratio might be too high for pump gas & a reasonable ignitiontiming curve.
305 engines have less volume per cylinder, so the heads have to have smaller chambers to maintain the same compression ratio (assuming the same style of pistons).

IF the CR is close to being tolerable, you can drop it a little with thick head gaskets. The 305 gaskets are likely too small for the 350 bore diameter. You don't want the edge of the gasket protruding into the cylinder.

 

[AC_DC_2001]

Before I tore the engine apart my CR was about 145-150 on all cylinders dry. I'm hoping to get an engine kit that comes with new pistons and rings, and other things. I'm guessing, since I'm not quite sure how to calculate it, that the CR with the 305 heads, new rings and pistons; and taking into the fact that I'm not going to bore the cylinders; I don't really expect it to be more than 165 psi. The CR for a stock 350 is 155. I don't beleive it will be a considerable problem, I just don't need to go hot rodding with it.

If these heads don't work out I always have my 350 heads to fall back on, and since I didn't pay anything for the 305's it's not the end of the world if I can't use them.