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Discussion Starter #1
In a few months I plan on building a 302 for my 1985 Ford F-150.

Stock Block
Bored .40 Over
Comp 31-255-5
250 Int./260 Exh. - Valve lift .462 Int./.474 Exh. - Lobe Angle 114 deg
Stock Intakes
Aluminum GT-40's
1.7 Roller Rockers

How much HP and TQ will that make?

Should I go with the aluminum GT-40's or go with different heads?
 

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.040 is a bit more than I would go on a stock block. Any reason you want to go with that size bore?

For the money there's better heads out there. Look at trick flows, victor jr's, AFR's ect.. The trick flow 170's are the best bang for the buck. If you do heads, that stock intake will be the choke point. And with the right cam, there's no need for 1.7 rockers. Are those duration numbers @.050 or advertised? .. either way, I probably wouldn't use that cam, even with 1.7 rockers, It's still pretty small on lift and if those duration numbers are advertised, which they probably are, it's a pretty small cam in general. You're better off talking to a cam company or a designer and telling them the specs on the truck, engine, and goals for the truck and they will be able to point you in the right direction.

Being an 85, is that carb'd?
 

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Discussion Starter #3
.040 is a bit more than I would go on a stock block. Any reason you want to go with that size bore?

For the money there's better heads out there. Look at trick flows, victor jr's, AFR's ect.. The trick flow 170's are the best bang for the buck. If you do heads, that stock intake will be the choke point. And with the right cam, there's no need for 1.7 rockers. Are those duration numbers @.050 or advertised? .. either way, I probably wouldn't use that cam, even with 1.7 rockers, It's still pretty small on lift and if those duration numbers are advertised, which they probably are, it's a pretty small cam in general. You're better off talking to a cam company or a designer and telling them the specs on the truck, engine, and goals for the truck and they will be able to point you in the right direction.

Being an 85, is that carb'd?
Well, I've heard that the more you bore an engine, the more HP it will make. So, I thought .40 would be good.

The duration numbers are advertised. Well, the truck is EFI and its speed density, so cam choices are limited.
 

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I'm not sure either. I've seen woody and outlawbill and a few others mention that a production 302 block is done after .030 so I don't plan on ever exceeding that myself.

To the op, the amount of power you'll gain from going .040 as opposed to even staying with the stock bore will be nothing that you'll even be to feel it will be such a small gain. You're only going from 302 cubes to 308 at a 4.040 bore. 6 cubes is nothing as far as power goes.
 

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put a stall in the truck or any cam other than stocks gona suck dick from a take off. When the engine dies in my 91 F150 Im just slapping in an explorer one
 

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Discussion Starter #7
Well, how much HP and TQ should my 302 make If I go with the Comp 31-255-5 cam and the GT-40's

Should I get new aluminum GT-40's, or get a used set of iron ones? Any advantages with the aluminum ones?
 

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Noooooooo....Go with AFR 185s or bigger. Better yet go trick flows.

Trick flow 170 flow about the same as AFR 185
 

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I have AFR 185 heads on my motor. Well i motor that i havent installed yet. Im sure ill be happy with the AFR, but if i had been given a choice i would have gone with trick flow 185 or bigger. But the 170 from what im told are also a good head and can be ported to flow much more, should you ever go that route
 

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Go .030 over, .040 is ok on a stock block, but why go larger than needed? Also, why worry about heads guys when this guy is using a stock intake mated to whatever he puts on?? I think GT40's would be fine, in cast iron, available for around 300 used or less, make sure the ones you get are reworked and have upgraded valve springs.
What is your plan for the truck? Highest hp, more torque, towing, drag racing, cruising? what? that determines what direction your engine build should go.
 

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I may get a little crap over this but I have ran the Pro Comps alm heads around 600ish for complete set of heads. I have ran these for the past 3 years on a 94 turbo cobra and have no issues at all with these heads and they work great. these are the 2.02 1.6 and flow 210 cfm. Just thought I would put this in there.
 

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steveofire;3614632[B said:
]I may get a little crap over this[/B] but I have ran the Pro Comps alm heads around 600ish for complete set of heads. I have ran these for the past 3 years on a 94 turbo cobra and have no issues at all with these heads and they work great. these are the 2.02 1.6 and flow 210 cfm. Just thought I would put this in there.
You're right, lol. Those heads are hit or miss with casting. I've seen documented cases where the valve seats have dropped out of the head while on the car. Even if you get a set that doesn't have casting flaws, what kind of valve train comes with a $600 set of complete aluminum heads? At the very least I would get those bare, have a professional go over them, and then put good valve train parts in them.. but by that time, you could have bought a set of good heads for the same $ spent.
 

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Here is the specs on the heads and I know they used to have a bad rep for having issues with the castings but that was a few years ago and everything I find now no one has been having issues with them.

Aluminum Cylinder Heads Feature-

* Hardened Seats
* Bronze Valve Guides
* High Grade Aluminum
* Multi-Angle Seat Design
* Available Complete or Bare
* Available fully CNC Machined
* Designed Performance Valve Springs
* Advanced Port Design for Greater Flow
* Combustion Chamber: 60cc
Intake Runner: 210cc
Intake Valve: 2.02"
Exhaust Valve: 1.60"
Spring Pressure Closed: 140 lbs. @ 1.800"
Spring Pressure Open: 325 lbs. @ 1.225"
Retainer Material: Steel
Valve Seal Material: Viton
* Valve Guide Material: Manganese Bronze
Valve Job: 3-angle

Here is a rundown on the hardware we are using

NON MAGNETIC, stainless steel valves, swirl finished one pc. undercut. The same valve we have used for years, with zero failures. Non magnetic is very important. Our cost on these valves is around double the price of some of low cost valves on the market. We know for a fact that many head builders use these low cost magnetic valves. We do not use them and never will. If the valves pull a magnet, they are not high temp stainless. They may be stainless, but they have very low nickel content in them. Stick a magnet to your stainless kitchen utensils; it will pull a magnet very strongly. Kitchen utensils are made from 400 series stainless, and have very little nickel in them, as they don't encounter extreme temp ranges. It is the higher nickel content that allows a valve to withstand high temperatures.

Our springs are USA made, 1.46 diameters, with an internal damper. Others are using springs that are much smaller in diameter. Smaller diameter springs may be in the correct spring pressure zone, but they are usually very short lived. Zero failures with our springs. The springs in this setup are to operate with hydraulic roller cams up to .710 lift. For those running solid or roller cams, see our other listings for heads built for these type cams. We have also seen spring kits on the market that are larger in diameter, but are made with much thinner coil material.

The Comp Cams 10 degree lock and retainers are chromoly steel, as well as the id locators.

The screw in studs are included.
 

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Like I said, valvetrain is pretty sketchy. 325 lbs open pressure and they're good to .710 lift? That's probably fine if you're building a diesel with a 3500RPM redline. Other than that, I see some valve float on a decent cam at higher RPM's. No name valves, so who knows what you're getting. They could be ok, they could be crap. They don't give a weight.

Not picking on you personally. You may have had good luck with them. But when I've seen more than a few engine builders say they're garbage and they'll never work with them, and seen cases where people have posted pictures of valve seats dropped, it says something. If they've been gone over by a professional and have quality name brand valve train components, sure go for it. But I wouldn't risk it the way they sit for $600, and like I said, after you spend the money on good valvetrain, you've got as much into them as some victors or twisted wedges or AFRs and they only flow 210. GT-40P's flow 185 straight off an explorer. Just my take on them.
 

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Discussion Starter #18
Go .030 over, .040 is ok on a stock block, but why go larger than needed? Also, why worry about heads guys when this guy is using a stock intake mated to whatever he puts on?? I think GT40's would be fine, in cast iron, available for around 300 used or less, make sure the ones you get are reworked and have upgraded valve springs.
What is your plan for the truck? Highest hp, more torque, towing, drag racing, cruising? what? that determines what direction your engine build should go.
You know..I was seriously debating whether or not to get the Iron GT-40's or aluminum ones. Right now I'm really leaning towards getting the irons, since I am on a limited budget and I'm using the stock intakes.

My plan for the truck is just to have a respectable amount of HP and TQ. Just looking for quick acceleration.
 

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You know..I was seriously debating whether or not to get the Iron GT-40's or aluminum ones. Right now I'm really leaning towards getting the irons, since I am on a limited budget and I'm using the stock intakes.

My plan for the truck is just to have a respectable amount of HP and TQ. Just looking for quick acceleration.
If you do GT-40's for cost reasons, go irons. Don't waste the money on those aluminum ones, there's much better heads out there for the cost of aluminum GT-40 heads.
 
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