This was a big selling feature on the GT40 heads for me. Since my 302 had very low miles at only about 35k, my pushrods and rockers were all like new. The aftermarket aluminum heads are nice, but the simplicity of keeping with all the factory parts was nice, especially for a rarely used street truck.

 

That's good to hear. I didn't know that. I can pick up some GT40 cast iron heads factory reman by ATK but for $1,200 for a pair of reman GT40 cast iron heads or spend $1700 with upgraded springs and studs for a pair of aluminum AFR 165 heads. I decided on the AFR heads as the aluminum should allow me to run middle grade 89 octane gas at 9.5:1 compression considering 10.5:1 is the generally accepted limit of 93 octane pump gas with aluminum heads.

at work this morning I took time and cleaned up and bundled the set of Comp push rods I might be able to use them but considering the engine they came from was a flat tappet with roller rockers I highly doubt I can use them on a roller cam application with roller rockers. So looks like I got a set of comp pushrods I am going to be selling to recoup some money. Even at $50 for the set is good for everyone as they don't look bad and I didn't buy them they came off a customers blown motor when a valve head broke off and dropped into the cylinder. Same goes for that old late 60`s Edelbrock 289 intake I see people over on the hamb are buying them up used for $250 - $300 for their period hotrods. Also got a set of aluminum M/T valve covers for a 302 I wont be using either off the same motor.

 

You should be able to regular 87 at 9.5:1 even on the GT40's as long as you don't go too crazy on the initial timing. There should be no need to run mid grade on 9.5:1 Mind you this with our fuel it may vary region to region.

 

I was leaning towards trying for around 12* btdc initial. my stock 302 loved 12* and I think a 9.5:1 compression 306 with a roller cam should be able to handle 12* initial as well. I want to play with my dist as I got the advance kit that has advance springs and an adjustable vacuum advance. want to play with it and custom tailor my mechanical and vacuum advance from there.

If I can get by on 87 regular that would be great for me. I bought 93 for my 56 even though its 8.5:1, want to run a couple tanks of 93 through her first before I try going down to see if my spark knock comes back on that engine. But that was bad at $2.99 a gallon for 93. Once I move the 93 is ethanol free but its about $0.40 more than here so right now it would be like $3.39 a gallon. I couldn't handle that for a daily driver truck with the aerodynamics of a brick being forced to drive highway everywhere at 70 - 75 mph lol.

 

I try to keep stuff around 10° BDC on the small blocks so 12 is not bad but base is a function of where you end up in total advance.
So all you can do is shoot for a setting and hope you end up near there once the total is dialled in.
Unless you have particularly bad fuel in your area 9.5 on regular should not be an issue.

 

I was able to swap out my cracked head for a set of GT40's. I noticed the head bolt was too small so I used a 17/32" drill bit to widen the hole. The weirdest part of it all is that the other head already had holes large enough to accept the larger 1/2" head stud, and only the one head needed modified. I pulled them both from the same '97 Explorer and the head gaskets on both looked to be stock.

 

The 302 uses smaller head bolts than the 351w. They make special washers to use 302 bolts with the 351w heads. But the way Ford operates,, and the 302/351w getting near the end of it's production run, I would not put it past them to use whatever they had. They must have special wide head bolts if it didn't have washers. There really no difference in the later 302 and 351w heads except the bolt hole size.

 

Well all the bolts were definitely the same and they weren't shouldered or anything. Definitely odd to see both on one engine. They'll both accept the 1/2" head bolts now so I'll lap the valves, install new seals, and put them on.

 

I started disassembly of the second head today and the valve seals are of a different type. The 1/2" head stud head uses the same style seal that was in the head that was cracked (out of a '92 351w) and the 7/16" head stud head has a brass cup style seal.

 

One of the valves has a horizontal scratch near the end of the stem. The scratch is deep enough my fingernail catches on it. What can I do to get it all back together?

 

Does that part run in the guide when installed and working or is it above the top of the guide?
If it is in the guide I would most likely replace it and check that guide real good to make sure it is not scored from the that.

If it is above the guide I would take a fine file to it to make sure it does not have a high spot to hurt the guide when installing the valve.
Do you know what guide it came out of? Check it good for damage.

also how did that happen?
Dave ----

 

Well that valve was removed from the guide so it is scored now. The area of the valve is way above the guide. So he should be able to just dress it down with a fine file and reuse the valve.

 

After I typed out the post I saw the bigger picture and saw it was above the guide but you are right on it messing up the guide when pulled and why I said it needs to be checked if he knows when it came from.
Someone would have had to yank that one out. If the valves don't fall out stop and find out why.
Sometimes the valve tip can et mushroomed over and needs to be cleaned before it can come out.
Dave ----

 

I ended up using 320 grit then 400 grit sandpaper to sand the spots down. I didn't have any problems removing the valve from the guide but it is definitely above where the stem travels into the guide during normal operation. It's all back together now. The heads should go on the engine tomorrow hopefully.

 

So I've got a 2181 Edelbrock performer as well as a 1406 carb. Is anyone running this combo? I can't figure out how to connect the throttle cable. I have a 1491 part but that doesn't seem to help.

Edited: used to say 1421 not 1491