5.0 GT roller motor's?

289 - 351 cid Small Block Performance
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Lip Ripper
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5.0 GT roller motor's?

Post by Lip Ripper »

The engine in this falcon is a 93 with an F303 cam. It run's out of steam at 5800 when you free rev it. I have read that this cam likes a stronger valve spring. And I will also say that I have not touched this motor. I haven't read the timing or the advance curves; just curious if this is where everyone else is. In my mind this should rev past 6000 rpm's like nothing. I'm thinkin the spring's need to be replaced.

Stacey
66 Cyclone GT; 245/60R15's on 15x8's and 215/70R15's on 15x7 Magnum's.
There's nothing like the sound of a pushrod V8 singing at the top of her lung's.

Comechero65
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Re: 5.0 GT roller motor's?

Post by Comechero65 »

AFAIK the F303 should be a truck cam which means it has its' power curve in the low rpms not the top end so not surprising it runs out of steam near 6000 rpm. For me that is the ideal as that makes a good street cam for everyday driving. I replaced a B303 cam with something similar for those reasons plus i wanted something with a good idle which the B303 did not.
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Rocket989
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Re: 5.0 GT roller motor's?

Post by Rocket989 »

The F303 is actually a pretty stout cam in a 302...though the timing events are not great for stock/ stock'ish iron heads. It's popular as a low-buck turbo/ blower/ nitrous cam due to using 114LS.

Depending on how the cam was installed, the heads, intake, carb, etc. I wouldn't expect it to make power much past the late 5's.

If you think the valves are floating a bit I'd look at a spring with at least 120lbs. closed and minimum 280lbs. open. IMO, even the B50 springs Ford used to sell for their letter cams were not enough - especially on motors that'd buzz!! :mrgreen:

On the brothers 302 using a Comp 270HR cam (same lift as an F cam, little less duration, and a more friendly to semi-challenged flowing iron head 110LS) IIRC he used springs that were like 130/ 320 at correct installed height. No issues to date.

On the 302 I'm flogging on for the Comet (using a FRPP "B" cam and 1.7 rockers - similar to an F cam with 1.6's) I picked springs that are ~125/ 290.

Specs for the "Letter" cam's:
https://performanceparts.ford.com/downl ... tSpecs.pdf
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Lip Ripper
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Re: 5.0 GT roller motor's?

Post by Lip Ripper »

I have the 270H in my FE. It pulls hard and I shift it at 5700. It'll run up to 6k pretty easy but it's done at the 5700 rpm range.


I think I need to increase the spring pressure. Thanks for the input.
66 Cyclone GT; 245/60R15's on 15x8's and 215/70R15's on 15x7 Magnum's.
There's nothing like the sound of a pushrod V8 singing at the top of her lung's.

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fryedaddy
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Re: 5.0 GT roller motor's?

Post by fryedaddy »

was your engine up to temp when you reved it,my buddy has one that wont rev good till its up to temp,i dont think those roller motors rev much above 6k anyway.i bet its going to be stouter than you think,when you get the bugs out,good luck
fryedaddy
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popscomet
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Re: 5.0 GT roller motor's?

Post by popscomet »

fryedaddy wrote:was your engine up to temp when you reved it,my buddy has one that wont rev good till its up to temp,i dont think those roller motors rev much above 6k anyway.i bet its going to be stouter than you think,when you get the bugs out,good luck
pop WON'T REV an engine til it's up tp normal operating temp to start with////but that's just me maybe,I don't know////////
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poboyjo65
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Re: 5.0 GT roller motor's?

Post by poboyjo65 »

Pop you know I don't rev before it is warm. I had a few ask me at PF what I was doing sitting there idling. I said waiting on it to warm up! I always give it at least 5 min.
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fryedaddy
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Re: 5.0 GT roller motor's?

Post by fryedaddy »

i dont rev em cold either,never,never,never, but i saw a guy buy a gt mustang,302 roller,he revved it up and looked at me and said,whats wrong with it,i said duhh,you have to let it warm up first,same guy i was talking about,i thought he knew better.i allways let mine warm up before i drive,but let me tell you a story.my papaw had a ltd, after he was retired the only time he drove his ltd was to church on sundays,only 1/4 mile away.he used to start his ltd when he had not driven it in a while and let it run for 30 minutes or so.his engine had no compression at 40,000 miles and it had to be rebuilt.he wore that 302 out idleing in the driveway and those short trips to church and back got it too.had nothing to do with this topic,just a story and jmo
fryedaddy
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popscomet
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Re: 5.0 GT roller motor's?

Post by popscomet »

NO that motor was worn not out from ideling,,,,,that motor was worn out from carbon build up....jmo pop
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lavron
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Re: 5.0 GT roller motor's?

Post by lavron »

Like my dad always said "You need to get that car out on the road and blow the cobs out of it!"

See Ya,
Mike
Mike's build thread
viewtopic.php?f=9&t=13058
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fryedaddy
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Re: 5.0 GT roller motor's?

Post by fryedaddy »

ripper,im sorry i got a little off topic here.i really am interested in your falcon build.cant wait to hear more about it as time goes by.
fryedaddy
Image1966 caliente,428 4 speed,4.11 gears,nitrous,parachute

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