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Discussion Starter #1
The 302 is from a late 90's explorer with 105k miles (thus the GT40P heads) and I really like the look and feel of a carburetor on the motor. I'm planning on rebuilding the motor anyway and since all of this has pretty much fallen into my lap at some great prices, I'm inclined to jump on it, but I would like some advice first.

My issue? I'm not an engine guy and I want to make use of great buys, without making my car act like I slapped what was convenient on it, for the sake of convenience.

I have heard from many places that using these motors in more of a race and street car setup you want to swap out the cams (any suggestions on one with this setup?).


The cars purpose will be to get up and go, to be enjoyed and occasionally abused. This is not intended to be a track car or a racer by any means. Just an enjoyable, semi-reliable, never-finished vehicle. I anticipate lots of use with work and play in the summer.
If you have a thought, or a criticism on the setup (keeping in mind my goals), let me know. I appreciate it and thanks!
 

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Non-whiner
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Go with a dual plane intake. The victor jr. is not right for your intended use.
 

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I've got an Explorer motor with GT40P heads. The cam is a Trickflow Stage I:Trick Flow® Track Max® Hydraulic Roller Camshafts for Ford 5.0L: TFS-51402000 - trickflow.com You'll have to replace the valve springs, I went with Crane beehives (p/n 44308-1). Manifold is a Edelbrock Performer RPM Air Gap with a Holley Street Avenger 570. Distributor is a Ford Duraspark built by DUI: Ford Duraspark
The motor was built by Fortes and dynoed at 345 hp at the crank. I'm really happy with it. Here's the startup:


and here it is on the road:

 

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for the intake I would go with Performer RPM or RPM air gap. A mild cam like the trick flow stage 1 or ford E or B. The heads run out of steam around 5600rpm, so the other parts should be spec'ed to that.
 

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agree with Trevor, these heads are going to be done at 5600 rpm with a 302-306 ci engine. Dual Plane with a semi mild hydraulic roller. If you are thinking about an engine rebuild, I would seriously look at all the aftermarket heads out there (aluminum or iron) vs putting money into a set of factory castings. All said and done it may cost a few hundred more but the improvement will be dramatic and it allows you room to add power as time/money permits in future.
 

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FFCobra Fanatic
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I have what you have, a former Explorer engine with now 120K on it.

I did not replace any valve springs or the head bolts. I did replace all gaskets. We did clean up the heads and now in hind site, would consider a port and polish job on the GT40P heads. You may want to see if you can shave the heads a little. The compression in stock format is somewhere about 9.6 to 1.

I have a very old phantom dual plane intake. It has worked well. A good alternative would be Weiand Stealth. Edelbrock also makes good dual plane intakes. We use a Holley 600 CFM 1450S and have used Holley's manual 199R-7948-5 to tune the carb.

My car has been on a dyno twice and we have made few adjustments; a more open air cleaner and the weakest vacuum advance spring that Holley makes. Its 327hp and 353tq at the crank.

If you go with an E cam consider 1.7 Ford roller rockers. I have them and they open things up well and will give you another 15 or so hp over an engine with the 1.6 rockers.

Use a spacer between the carb and the intake manifold, its good for 5 hp and reduces the chances of vapor lock. We have never had vapor lock on our car in about 23K.

We have used a Mallory Unilite distributor. It has worked well.

I have very very little money in this engine. The only way to really make more power is to go with a stroker kit, blower and/or heads. All costing in the end at least another $2k.

Good Luck.
 

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New heads will give more power. Look at rebuild cost for the P heads and gauge from there.

I picked up some low mileage used heads from the forum and bolted them on (some risk but no rebuild cost for the head).

I would not reuse the head bolts. You don't have to go top of the line ARP, just a good replacement.
 

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If you look at my sig line, I have a very similar motor, with GT40P heads, except that I have EFI. I can tell the heads are the choking point on the engine, but I do like the way it runs. This winter I am going to try to help out the exhaust some by only installing the 1.7 rockers on the exhaust valves, leave the 1.6 on the intake, and see if that helps even things out.
Anyone else done this?

Skip :white:
 

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I'm very happy with mine. Don't even mind the 5600 rpm limitation. It gets there real quick!
 

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when i first built my car it had the donor mustang 95k sb, chrome oil pan, new gt40p heads, 1.6 roller rockers, ford X cam, 4 into 4s, performer RPM, demon 650dp. It made [email protected], probably 320hp crank. It was a good motor. Really plenty of power for these cars. Easy to drive, no bucking, ran silky smooth all the way down to 1200rpm in 5th. Its perfect for a mild street cobra. Could go toe to toe or beat anything on the street up to 100mph.

Now my car has next to nothing under 2500, bucks like hell if you are under 2000 in a higher gear, hits like a freight train from 3000-6500. Nearly uncontrollable in 2nd under full power. Pulls rock steady all the way to 150mph in 4th. Its prefect for the race track.
 

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Dave

Mark at Breeze has a package that includes everything you need to use the Explorer motor. Breeze Automotive Factory Five Racing He's a great vendor and can help with any questions you may have during the build-up. You shouldn't really need to rebuild it with only 105K miles.

I have the same motor with the Performer RPM intake, Holley 570, and a Mallory Maxfire distributor. I used the Mustang HO cam and am very happy with the torque and great street manners. Oh it's also very fast. Here is my dyno run after my recent tune.



Jeff
 

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I'm maybe not a perfect example, but will share my experience anyway. I have a 91 roller block, bored .030 to a 306. I'm using AFR 165 heads, so a little different than your GT40P heads.

I agree completely on the dual plane intake. Researched this when putting mine together, and it was the overwhelming choice for mainly street use. I'm using an Edelbrock RPM Air Gap 7521.

Also researched quite a bit for the cam. I worked with COMPCam, and they recommended their 35-440-8 Magnum Hydraulic Roller cam. Adv dur: Int: 281, Exh 281. Dur @ .050: Int: 220, Ext 220. Lobe sep: 110.0. Valve lift: Int: .512, Exh: .512. I'm also using COMPCam 1.6 roller rockers. This setup is a nice compromise with decent street performance, little bit of a lopey idle, but still well behaved idling at 900 - 950 RPM.

I started with a Holley SA 570 carb. Ran good, but just a few weeks ago changed to a 650 double pumper with mechanical secondaries. This really woke up the motor. I couldn't be happier with the change. I know lots of guys use the SA 570 carb and are happy with it though. Probably for your setup with the GT40P heads, may want a 600 vs. a 650.

This is my first start video, so you can get an idea. I'm done and legal now. Very pleased with how it runs. I will only be using on the street, and it gets in more than enough hurry for me.

 

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FFCobra Fanatic
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When you buy an Explorer engine with the GT heads, which ever one, you are paying a premium for a Explorer 5.0 because of the heads and the intake. If you remove both of these parts then you are buying the engine for the short block and there are low mileage 5.0 engines that are less expensive.

My short block cost me nothing by the time I sold off the EFI intake, PS, AC pump, alternator and bracket and surprisingly the gold plated exhaust headers. I don't think I could do that today, its been a few years.

Trevor's experiences are mine with big HP engines and he has done a good job of explaining the differences. There is price to be paid every time you work to get that HP sucker started and then keep it running at the speed you want to have it run.

Mine is strong to 120, sure there are a few cars in the club faster to 120 but not by much and by then a cobra is all out of aerodynamics, and you need stuff to keep it on the ground.

Good Luck!

Rick
 

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Discussion Starter #14 (Edited)
Fantastic!

Videos, advice, everything.

For the pricing part on this motor, it is in good running condition for $300. I don't think that is a bad deal. I know you can get the blocks and such for about $100, so adding some heads and planning on rebuilding it for experience, knowledge and fun, I think why not?

It sounds pretty unanimous about the Victor Jr. not being the right one. I will definitely reconsider and look around for a Dual Plane.

As far as the heads giving out at about 5600 RPM, that is very good to know. That's not something you can just fix with new internals, such as cams? Not without a fight?


**Doing more research after reading, it looks like the Vic Jr. is a high RPM intake, while the Performer is the low RPM. You see, that's why I come here, you guys help me figure all this stuff out before I put it together and think... 'Why is my car garbage?!'

Thank you!**
 

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cam wont help it is the port volume and size. Its a decent head for the money.
 

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I once ran the GT40P heads with a B303 cam and a Victor Jr with a 650DP Holley and it ran great. Alot of power on the top end say from 4 grand up but I was also running 3.73 gears so I still had plenty of bottom end for stop and go driving.
 

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FFCobra Fanatic
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Make sure you get a dual plain, air gap intake. Several mentioned here. Also, add a 1/2" four hole spacer under your carb (again good carbs mentioned above - Holley).
 

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Big Kahuna
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5,671 Posts
RPM Airggap, B303 cam, GT40X heads and FAST EZ-EFI here. Love it! Awesome bottom end, pulls strong to redline.
 
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