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Discussion Starter #1
What kind of power do you think i have with 85' 351w bored .060
544 lift cam small tube headers with flows dumping
High-rise dual plane with 600 holley MSD 6AL matching wires and coil
302 heads roller rockers
I cut the heat exchange out of the exhaust ports and polished all ports
1989 Mustang LX 4 cyl. car
Still using the stock 5 speed

What rear end gears came in it stock
 

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I'd say 300 to 350.

First off, that carb is way too small. I guarantee you are running lean if you have an 1850. Go with at least a 650. A 4778-2 is a 700 double pumper. It has the bell shaped truck boosters. It would be perfect for your engine as it is right now.

You are running stock Ford heads, they are a major restriction. I would have suggested a 750 + carb, but with stock heads you won't be flowing much air. In fact, your cam won't work as it is supposed to with stock heads either. Everything over .480" won't increase flow, so all that valvetrain movement is for nothing.
 

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Discussion Starter #3
Thanks for the info

What is the cheapest way to improve the heads, New? more port work?

I have a 750 double pumper so i might jet it down?
 

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Go with aftermarket heads. The stock castings aren't worht the machine work.

Jetting a carb down does not make it work on a smaller engine. You will just end up with a carb that is too big and running lean. The 750 is going to be too big at first. At least you will have it for later when you are making enough power.

I would guess that you will need to jet your 600 up two sizes in the front. Use a lighter, if not the lightest secondary spring.

Remeber, 2.02 valves usually need clearancing to clear the stock pistons. You are running a fair amount of lift. You will have to do your homework to find a head that will work properly.
 

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Discussion Starter #6
What aftermarket heads are the best for me?
Can I add a 75 shot with the stock pistons
One more : How high can i turn the rpm's
 

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gt40 heads would give you a good boost. As for the rpm and 75 shot it would all depend on you. better to hook up to your throttle. rpms wise.. your looking at max 7000. I had gt40 heds on my 89 5.0L with NO5 wired to the throttle, and man did she move.
 

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Gt40 heads don't flow enough to be worth paying for. I have seen a few independent comparisons. The GT40s and the GT40P heads were very unimpressive.

These are good:
Trick Flow Twisted Wedge or Track Heats

AFRs

Any of the World Product heads


I have a set of Track Heats. I haven't done any more research on Ford heads since I bought them 3 years ago.

Here is a good article. I am trying to find a comparison that I remember seeing. I'll post it when I find it.
http://www.mustangworks.com/articles/powertrain/CylinderHeadScience.html
 

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gt40 heads usually put out 60-80cc.. afr heads put out 170-205cc. But for a 351, why would you need over 170 cc...?? Maybe if he had 600 horse in that bad boy. PLus AFR heads are hella expensive, gt40 heads are around 350 bucks.. afr They start at 750.00 and go up to 3300.00. I guess it would be a better head to use if you wanna fork out the dough.
 

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the GT40P heads are a factory casting and outflow the old gt40 iron heads, the only draw back is that you need GT40P specific headers, whitch isnt a problem with the fox chassis, I believe Coast High Performance offers affordable headers for the GT40P heads..


you might also want to check out PTL's 200CC iron heads or alum, there is a member @ www.corral.net in the 11's with out of the Box PTL iron 200cc I think he said he picked them up from summit on sale... may be worth checking out...

you can also browes Corral's classifieds for used aftermarket heads, you may very well be able to pick up a set of alumin heads for the price of new iron heads...HEY! GL!

2wld4u
 

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Still the GT40P heads have weak flow numbers. The main turn off about them is the exhaust to intake flow numbers. You want 75% to 80%. I can't rememeber what they came out to, but it wasn't in that range.
 

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As far as RPM is concerned, 7000 is alot for a 351, your better off with a max of 6000 to 6500. One thing that alot of the 302 guys forget is that the 351w has about 20% more bearing speed with its big 3" main journals. The same bearing speed a 302 see's at 7000rpm you will see at 5500rpm.
 
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