Thread: 1970 302

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I put a 70 302 in my 65 custom 500 and I think this motor is on the edge of needing more then regular gas even though its a 2 bbl motor,does anyone know what the compression ratio is for this motor. It has less then 20,000 miles but I doubt it has hardened seats so I might be looking for a newer set of heads that have a slightly bigger combustion chamber and would like to know what ones to use that would flow similar to the 70 heads. When the compression was lowered in the early 70s was it in the heads or were dished pistons used,since this motor has low miles I really dont want to tear into it but it does have one lifter making noise from the 30 year storage so a change to a 4 bbl will happen when I replace the lifters but I am also thinking about changing the timing chain to get rid of the plastic cam gear that might come apart from age so I while the front of the motor is off I would like tp put in a little hotter cam and if I have it that much apart I might go ahead and put on a set of heads with hardened seats while I am in there. Jeff

well if you're going to go 4bbl on it, i'd reccomend just swapping the cam and get a edelbrock cam, lifter, rocker, pushrod, intake and carb package. the cam gear shouldn't be plastic it should be nice hard iron possibly even nodular iron. the compression drop ford did was chamber size on the heads. a 70 302 should still have around 8.5:1 compression ration..... if you want some heads with a little better flow but still keep the compression down, get some AFR 165s with larger chambers, go for like the 64cc chamber or so... i personally run 58cc heads, but i like compression...

You didn't say if your 302 was chevy or ford chevy 302 had 11:1 comp.

this is posted in ford small block so i'm pretty sure its ford 302

Before busting the motor apart,,,,,,use sum marvel mystery oil........run it few hundred miles....then change oik......should stop the noise

if something is wrong then all thats gonna do is hide the problem and cause a break down later... thats like changing to heavier weight oil because you have a rod knocking, its still knocking, you just cant hear it

Marvel cleans not coverup anything.......Fords get a varnish in the lifters...it dont cost much just to try and clean them up...If Marvel dont work....spend BIG Bucks

If you go to a 74 or 75 head, you will get a larger cc head. Also, an early set of 351W heads will have better flow then the 302's, and larger cc chambers. If you could find a set of 69 to 71 351 heads, you would get the best of both worlds, larger chamber and better flow. If you go past 76 on the 302 heads, then you get into some larger chamber but lousy flow heads...... Like Mr. Hurley, I've used Marvel to free up a lot of sticky lifters. The Windsor engines really seem to like the Lucas oil additive once you get the lifters working right. As far as the cam, Summit sells a nice mild street cam with their own brand on it for about $80.00 with lifters.....