1968 302 heads or 1980 302 heads?

1968poney · 01-19-2009

Ok i have a 1968 mustang and i am rebuilding a 302. i have a 1980 302 and a 1968 302. the heads are diffrent. does any one know which one is better. the heads on the 1968 are more open in the cylinders and the 1980 are more pushed into the cylinders. i also know the 1968's have stud rockers and the 1980's are bolt in. i also know the block on the 1980 is missing the hole for the clutch bar, but found an adapter that bolts behind it to have the bar work. I wouls asume that the newer heads would be better but could be wrong. O another thing on the 1968 engine the pistons have this center cavity not for the valves and the 1980 engine has just the cuts for the valves is there a diffrence regarding volume or just weight.

Tom

RemRem123 · 01-19-2009

I would stick with the '68 heads, they flow better. The '68 302 made about 220 hp while the '80 made about 130 hp. big difference, and while it may be due to other things, a big part is most likely in the heads, the '80's were also configured to help with emissions, so that cut into power

nigel · 01-19-2009

I would stay with the 68 heads for the same reasons but I would use a set of 289 heads if I had them.

1968poney · 01-19-2009

I have 289 heads that came off my 1968 302. Do you think it will interchange on the 1980 block with pistons. cause i also was questioning why there is a circular depression in the pistons on the 1968 engine and not the 1980 engine Im not talking about for the valves either. there is a whole circle and thanks for helping

mustanglover66 · 01-21-2009

The pistons in your 68 are dish pistons which makes the compression lower to about 9.5 to 1 most likely a 2 barrel engine. The 80 has flat top pistons which make a little higher compression with the 68 heads should put it around 10 to 1. With 10 to compression you will need to run 93 octane gas. But will give you more power.

1968poney · 01-21-2009

Makes sence thanks but do you think the 289 heads are better then the 1980 heads? O what about the smog hole i noticed on the heads of the 68 are blocked off with a plate the 1980 is not i have to block it off correct if i dont what will happen brake the law would i lose compression two i really dont know about the smog hole thats new to me.

Thanks Tom

RemRem123 · 01-22-2009

switching to the 289 heads will raise compression because of the smaller combustion chamber, but it will still make more power than the 1980 heads, as for the smog hole, it should be ok, and if your car is a '68, check your states emission's inspection laws, in NC, if its older than 1992 (? around there), you don't have to have an emissions inspection

1968poney · 01-23-2009

Thanks, I believe the chamber is 54.5 cc and the 80 is 69 cc so i figured that withe the smaller chamber it will make the compression around 10-10.5 to 1. I shouldn't have a problem with emissions since where i am but thanks again for the help.