289 or 351 heads on a 302 advantage?

I used to use 65 - 66 289 heads - you gotta port em - for a street engine they work good. But now I go aftermarket or GT- 40.

 

I bolted a set of 351w (D0E 1970) heads on my old 260 and my current 306 in my Ranchero. If I was building another engine today I'd go aftermarket heads better bang for the buck.

 

I got a set of iron GT-40 heads, a set of Trick-Flow "twisted wedge" heads and 2 sets of E7TE's.. Even a set of stock E7 heads can put a car in the 13 second zone...
Just ask anyone that did..

 

Really??? How big is the bore in a 260 block???

 

The 260 has a 3.800" bore.

 

3.80 inch bore, the 351w heads had been milled and ported . The 260 was rebuilt and bored 30 over, the problem was stock 260 pistons are true flat tops with no valve reliefs and I ran a Comp cam 271S (.495 lift) the intake valves just kissed the pistons (Yes I checked Valve to piston clearance) . Once the car got up in the RPM band she screamed but she no bottom end off the starting line plus I think that piston is down in a hole a bit so compression was way down too. I pulled the 260 and put in a 306 with better compression (9.5) with those heads and a Comp XE274 Hyd (519 In and 523 Ex) cam and picked up a second at the track (9.50's to 8.50's in the 1/8 mile) I wondered if I put in a smaller cam at first what the 260 would've run.

 

The deck height comes from the BLOCK, not the heads. Disregard what he said, it is wrong. 351W heads on a 260-302 do NOT require special headers or intake manifolds.

GT40P heads are a pain in the butt, as you can't find many headers to fit them (although we do make ones for early Mustang with those heads) Regular GT40 are the best bang for the buck. E7 heads aren't as bad as some say,and I have a set on a motor making 385 Ft Lbs at the rear wheels to prove it, and it's a pretty mild motor.

 

I was thinking about the intake valve to bore clearance with a 1.940" intake valve those heads came with...

 

No 351w heads came with 1.940 valves. The "big" valves on the early heads were like 1.84 instead of the usual 1.78, if I remember right.

You are correct that valve to bore clearance could be an issue.

 

intake is a bit pricey, $500 and must use boss 302 pistons, I have one on the engine stand

 

The original 351W heads had 1.84" intake valves, you would probably have to notch the top of the block if you put early 351W heads on a 260. With the vast assortment of Windsor heads now available that can breath way better than the old 351C heads. The 351C head swap isn't beneficial like it used to be.

 

Your correct on that intake valve size!!! My bad!

 

Ok my question is, what all has to be done to a 1970 302 when you want to put on 351 heads?? thank you, hooty1

 

The 351 intake is wider than a 302 & won't fit. Intake bolt pattern on early 351 heads are different than the 302 heads.

 

Starting in apx '77 the 351 uses 302 heads...so, look @ chart on pg 1. see how the 351 heads you have compare(CR & vales) to the 302 heads you have.

 

Dont tell me, my engine is built, and I have been racing it for a few years. Tell him. LoL

This is an old thread anyways, I bet his is built as well.

 

Yeah, but this is proof people browse the Dead Threads...so good info should be presented.

 

Not sure if you guys had seen this or not. A guy by the name of Stan Weiss has a complete chart of cylinder head flow rates. Good info!