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FFCobra Craftsman
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Discussion Starter · #1 ·
I am looking at a 351W FMS crate motor but according to an engine builder I spoke with today I would have to make some modifications to the standard crate motor. He said I would need to change the oil pan, and water pump because of rotation. Is this accurate and are there any other changes I would need to make? I would love to hear from someone out there that went with the 385HP 351W FMS motor.
 

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I would recomend sending the engine out and having it balanced, After using about 12 of these motors in the last couple of years and having problems with 2 of them I now take them a parts and check the balance and also check the tolerances.
 

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I have a crate 351W from FMS with 4000 miles.
I did need to change the waterpump/timing cover because I wanted to convert to v-belt.
On the engine stand that was a piece of cake.
I understood a while back you can order the v-belt set up now. There was nothing wrong with the oil pan except to loosen it to remove the timing cover. For personal reasons I swapped the Victor junior intake with a Weaind Stealth. I highly recommend a 650 carb. I went with the BG 650 Race demon. For $4700 this crate motor made 405 flywheel HP or 336rwhp. More than the rated 385....with a high rise dual plane intake. The motor produced 300rwtq at 2800 rpm, peaked at 337 rwtq at 4500rpm and still made 300rwtq at 5450rpm. Wide flat usable power band and very snappy. The next season I ported the GT40X heads for $500. My FMS 351W now made 378rwhp(455+flywheel_ and 361rwtq. It made 330rwtq at 2900rpm, peaked at 361rwtq at 4600rpm and made 330rwtq at 5500rpm. Peak HP(378rw) was raised from 5800 to 6000rpm with head porting. I have pounded this motor MANY times. It is extremely reliable and runs 11.54ET at118mph.
No kicks on FMS 351W crate motors from me.
I could have paid 6500-7K for a local build. Today at $5,200 I still think the FMS 351W is a good bang for the buck. Just makes sure you break it in properly and patiently. Dump the 20-50 break in oil after 500-1000 miles. Move over to synthetic around 2000 miles.

[ March 07, 2002: Message edited by: JAM1775 ]
 

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FFCobra Craftsman
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Discussion Starter · #4 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by cobraman:
I would recomend sending the engine out and having it balanced, After using about 12 of these motors in the last couple of years and having problems with 2 of them I now take them a parts and check the balance and also check the tolerances.<HR></BLOCKQUOTE>

Cobraman,
What would I expect to pay to have it balanced/chk tolerances? What specific problem did you find with the two problem motors?
 

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FFCobra Craftsman
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Discussion Starter · #5 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by JAM1775:
I have a crate 351W from FMS with 4000 miles.
I did need to change the waterpump/timing cover because I wanted to convert to v-belt.
On the engine stand that was a piece of cake.
I understood a while back you can order the v-belt set up now. There was nothing wrong with the oil pan except to loosen it to remove the timing cover. For personal reasons I swapped the Victor junior intake with a Weaind Stealth. I highly recommend a 650 carb. I went with the BG 650 Race demon. For $4700 this crate motor made 405 flywheel HP or 336rwhp. More than the rated 385....with a high rise dual plane intake. The motor produced 300rwtq at 2800 rpm, peaked at 337 rwtq at 4500rpm and still made 300rwtq at 5450rpm. Wide flat usable power band and very snappy. The next season I ported the GT40X heads for $500. My FMS 351W now made 378rwhp(455+flywheel_ and 361rwtq. It made 330rwtq at 2900rpm, peaked at 361rwtq at 4600rpm and made 330rwtq at 5500rpm. Peak HP(378rw) was raised from 5800 to 6000rpm with head porting. I have pounded this motor MANY times. It is extremely reliable and runs 11.54ET at118mph.
No kicks on FMS 351W crate motors from me.
I could have paid 6500-7K for a local build. Today at $5,200 I still think the FMS 351W is a good bang for the buck. Just makes sure you break it in properly and patiently. Dump the 20-50 break in oil after 500-1000 miles. Move over to synthetic around 2000 miles.

[ March 07, 2002: Message edited by: JAM1775 ]
<HR></BLOCKQUOTE>

JAM,
Good stuff!! Being a newbie in the car/cobra world, how exactly do you port the GT40 heads? Does it just open them up to allow
more air flow? Is that something you would recommend I do from the get-go? How did you decide on the Race Demon instead of the Speed Demon or Holleys? Thanks!
 

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Jim,

If you are looking for a good set of heads you could try here Fox Lake

I have a set of the Stage 2 TFS TW heads on my carb'd 351. With a Barry Grant 750 and mild cam the car made right at 400rwhp. The car is extremely driveable. I had the heads milled and you will have to flycut the pistons to put a decent cam in it. Those heads will run you about $1,800 complete. You could sell you GT40 heads and put it towards those. I believe Ron can also port your GT40 heads.

Most of the guys going fast in mustangs are not using gt40 heads. There's nothing wrong with them. It's just that for the same money you can get a set of TFS heads or AFR heads which are better. It depends on how much money you have to play with and what you want from the car. You obviously don't need much hp to make this car fast.

Don't just take a dremel and start porting your heads. If you don't know what you are doing you will kill the flow and could even ruin the head.

Good luck.

Jim

[ March 07, 2002: Message edited by: Jim McGovern ]
 

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Listen to what Jim says. Porting and polishing is a real skill. Most head manufacturers offer CNC'd ported heads which are the best because of the consistency. Hand porting and polishing is hardly done any more.

There is also a company called Extrude Hone that pushes an abrasive slurry through the ports and even the intake manifold to achive a polished surface.
http://www.extrudehone.com/

Porting improves combustion performance and polishing the improves fuel/air flow. Definitely the way to go if you want max from your engine.

-Keith

[ March 07, 2002: Message edited by: 2FAST4U ]
 

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Jimmy,

Bring the engine over to my house and I will check all tolerances and have it balanced by Hall Performance and put back together before you get the suspension on that thing. If you want to do some port work--Hall Performance can do that also. He is very reasonable and is doing three of my engines now for me. Call me at work. Tim :cool:

P.S. We can change the intake, timing cover, and Waterpump while we are putting it back together.
 

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The problems we had were a very bad viberation, on one motor at 2500 rpm
problem was crank balance , other problem was wrong rod bearings that made the engine wipe out a set of bearings on start up. (and yes it was primed before start up)The other motors we used were ok. A balance job is only a couple of hundred bucks if you assemble.
 
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