I have a set of 302 heads that were just completly rebuilt.I want to put them on a 289, the heads are off a 74 302. Do the 302 heads flow much better,or not at all? Thanks
the port flow is the same between the heads, however the combustion chambers of the 74 302 heads are larger than the early 289 heads, and thus you will lose compression, and power.
There is no differents in flow but a big differents in compression. The 74-302 head has a larger combustion camber and will lower your compression not to mention they need rail type rocker arms. rebuild the 289 heads and have a good 3 angle valve job done. You should also have hardend exhaust seats installed
I'll jump on the bandwagon!
Don't bother with those heads.
If you want something better than the 289 heads in a stock casting, look for 69-73 351w heads.
Other than those, keep what you got.
can anyone tell me what putting heads from a 70 351w on a 68 302 does? does it help/hurt the power/performance. My 66Gt has this combo on it from the previos owner, and was wondering what this combo does and if I should leave or change it out when I get the car ready to drive?
Thanks, izzy jr (james)
putting 351w heads on an early 302 will aid performance due to the larger ports, but will hurt performance due to lower compression. there is however usually a slight overall gain in performance, especially if the cam is replaced with a larger one to take advantage of the larger ports.
putting 351w heads on an early 302 will aid performance due to the larger ports, but will hurt performance due to lower compression. there is however usually a slight overall gain in performance, especially if the cam is replaced with a larger one to take advantage of the larger ports.
The 351 heads have 60cc vs 302 at 58cc.
2cc difference can be more than made up with attention to gasket thickness.
Now, 289s had smaller chambers, as some early 302s may have, but it's still not huge.
So When I put headers/ new exhaust on the car what do you recommend I look for? I don't plan on making a dragster out of it, just something fairly quick and reliable enough to be a dd if desired but mostly going to drive it for a weekend cruiser. It has the original 3spd c4 still, plan to put a gearvendors over/underdrive behind it eventually to make it a little bit more driveable and not have to do to much drivetrain changes.
rebuilding anything but your stock heads will be so close to ready to put on aluminum heads it isn't funny unless you can get your cousins brother's roomate to do it for $20 bucks. might not be in your budget, but for a quick car that isn't a dragster ( what is a dragster nowadays anyway? ) aluminum heads seem right to me. doesn't cost more than any other part you would put on the car :\
Back in '92 I rebuilt my 302 and went w/ the D0OE 351W heads. Shortly after I got the car on the road aluminum heads started popping up all over the place. Now the heads are somewhat cheaper now then they were. Also w/ aluminium ya can get by w/ a little higher compression. BTW I'm runnin Tri Y headers. Great for earlier chassis.