This is topic Could I benefit from a different cam(GT40 iron/2031)? in forum Tech Talk at Northern California Ford Owners  .


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Posted by LX Pony (Member # 2216) on :
 
Hey, I just discovered your board, and alot of good cam talk on it.My current combo is: GT40 irons, 61.5cc, bowl worked/gasket matched/5 angle,GT40 intake w/ported lower, Crane 2031 cam(214/220, 520/535 w/ 1.72s, 3.73s, FMS shorties, smog/AC delete, 101K stock shortblock.

Best ET:12.76@108.16
1.90 60ft

rwhp:288@5200
rwtq:322@3800

I retarded the cam 6 deg using my FMS chain after I ran the time in sig. Dyno was done after. I'm surprised my HP peak was so low considering I retarded the cam.I also run a 1" intake spacer for valve cover clearance which doesn't help.

I haven't been able to better my best ET after retarding the cam. I've run a best of 12.87@108.57, with a worse 1.9760ft, in similar conditions, but at a different track.

Could I benefit by going to a B,E, or maybe even an F cam? I would run my 1.7s with the B or E. I see that 93 Pony recommends installing the E 6 deg retarded also. How about the B? Would this smooth out the idle? I know somebody who has a B cam with ported stock heads, stock exhaust and intake, and you can barely tell it has a cam, but it wasn't installed by the dots. Most B or E cars I hear are lopey as hell though. I appreciate any help or input, sorry to make it so long.
 

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Posted by Pro50Eric (Member # 2065) on :
 
with the head work you've already done, going back to a B or E cam is gonna kill some of your hp. I'd recommend going to the F cam. It works great with power adders if you ever decide to get one, and pulls extremely hard, as has a hell of a lope to it.
 

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Posted by LX Pony (Member # 2216) on :
 
Do you think the F would work with my 3.73s? I know somebody who had an Fcam with stock TW heads, and he went just as quick with his 3.73s as with 4.10s, in a lightweight coupe.
 

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Posted by Pro50Eric (Member # 2065) on :
 
yep it'll work fine with 3.73's.
 

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Posted by shade-tree (Member # 298) on :
 
Not sure if an alphabet cam will get you what you're after? Perhaps a custom? Or a TFS stage 1? Or a compcam 264HR?
something like that...

By the way, I have a similar combo, '94 cobra longblock (untouched) and I've run either the edelbrock performer or the performer RPM intakes on it with longtubes, off-road, borlas, and bypassed PS and smog with a short belt.
at 3150#'s raceweight it's gone 12.52 @ 108.3 w/1.73 60' (this is with the RPM upper). Fastest with the performer upper is a 12.55 @ 107.9 w/ 1.71 60'

I'm swapping out my GT-40 irons (which I have grown to love, btw) for some TFS TW heads I've had for a while and an off the shelf Anderson Ford cam (N-41). If I'm lucky, I'll pick up 4 tenths and 4 mph but that's asking a lot, IMHO.
 

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Posted by 93PONY (Member # 60) on :
 
You moved it 6 degrees retarded from dot-to-dot, or 6 degrees from 'straight up'? 6 degrees from dot-to-dot would give you a 113ICL. I think the 2031 cam would work best on a 118ICL. However, it is a limiting cam. It has less overlap & a smaller intake lobe then all 3 of the FMS cams. Yes, you could definately benifit by going with any of the FMS cams.

I'd suggest something a little more powerfull though...
Is smog a problem??? If so, the Comp XE270HR on a 112LSA would work excellent. If smog isn't an issue.....there are quite a few good XE cams that will make some power.
The real problem is Comp cams are expensive. So, if you were going to spend that kind of $$$ I'd suggest getting a custom from them.... I could spec you out something if you like. Customs from comp are the same price as their off-shelf cams.

 

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Posted by LX Pony (Member # 2216) on :
 
I was hoping you would reply. I retarded it 6 deg dot to dot, so it's supposedly on a 113 intake cl. I didn't use a degree wheel, just the FMS chain. I like the fact that the FMS cams don't have the exhaust bias on them. I might consider having you spec out a comp custom...I'll let you know.

Did you ever get to run the car with the E cam which you installed 6 deg. retarded? Would retarding it smooth out the idle? Any experience with the F cam?

Emissions aren't a concern...offroad exhaust, no smog anything on the car. My 2031 has a nice idle, and great driveability, but I think I might be leaving some HP on the table with it. Thanks for the help, and if you have any more tips for my combo, I'd appreciate it!
 

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Posted by 93PONY (Member # 60) on :
 
The 'E' cammed car that I set up on a 116ICL is down with a toasted clutch. I haven't heard back from him on how it runs at WOT. He said idle was just as smooth at stock, but it idles at 1000rpm & he hasn't brought it down yet.
91PONY's E cammed car idles great at 800rpm. I'll be retarding that cam to a 116ICL in a few weeks & get it out to the track for some results.
The F has 2 degrees LESS vavle overlap @.050 then the E. It'll make power, but there's better grinds out there.

If smog isn't a concern, there is quite a bit left in the combo! I could spec out a cam that has 5+ degrees of valve overlap @.050 & still idle smooth at 8-900rpm. I'd probably spec out something with a slight exhaust bias just because typically GT40 iron heads are lacking on the exhaust side. If you had flow #'s on the heads it'd help out a lot.

What valvesprings do you have?
What power level are you looking for & at what RPM?
 

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Posted by LX Pony (Member # 2216) on :
 
Hey, I don't have flow numbers for the heads, but my best educated guess would be around 215/170. The bowls were professionally smoothed, as were the top of the exhaust runners, gasket matched to a 1250/1415, 5 angle valve job, and they also have some good dual springs and really good locks and retainers, no problem there.

I'd like to keep shift points to around 5800 or so max. Right now I'm shifting at 54 to 5500, and I hit my peak HP at only 5100, and again at 5300 on the dyno. I do want decent driveability, and I would like to stick with 3.73s, though I wouldn't rule out 4.10s.

So out of the Ford cams you would take the E over the F, despite the extra 6 deg of duration? What do you think of the B cam, just curious. Oh yeah, I also have the 1" spacer on my intake, which I'm sure I could change if I needed. I'll definitely let you know if I want a custom spec'd out.
 

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Posted by LX Pony (Member # 2216) on :
 
Shadetree, I've also thought about going with some TW heads along with a bigger cam. You're really doing good with that combo, considering it's a stock shortblock...wow. Does it have a cam?
 

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Posted by 93PONY (Member # 60) on :
 

quote:

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Originally posted by LX Pony:
Hey, I don't have flow numbers for the heads, but my best educated guess would be around 215/170. The bowls were professionally smoothed, as were the top of the exhaust runners, gasket matched to a 1250/1415, 5 angle valve job, and they also have some good dual springs and really good locks and retainers, no problem there.

I'd like to keep shift points to around 5800 or so max. Right now I'm shifting at 54 to 5500, and I hit my peak HP at only 5100, and again at 5300 on the dyno. I do want decent driveability, and I would like to stick with 3.73s, though I wouldn't rule out 4.10s.

So out of the Ford cams you would take the E over the F, despite the extra 6 deg of duration? What do you think of the B cam, just curious. Oh yeah, I also have the 1" spacer on my intake, which I'm sure I could change if I needed. I'll definitely let you know if I want a custom spec'd out.

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quote:

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Originally posted by LX Pony:
Shadetree, I've also thought about going with some TW heads along with a bigger cam. You're really doing good with that combo, considering it's a stock shortblock...wow. Does it have a cam?

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thks, whatever the '94 cobra came with is what's still in there (cobra cam, 1.7 rockers, GT-40 irons). Can't wait to pitch that stuff, heh starting today.
but yeah, it's pretty light, 2950#'s with 1/8 tank and I typically am running 3150#'s raceweight.
There's a guy local to me and he couldn't get out of 106 mnph land with the exact same combo but of course he was running a solid 200#'s heavier.
 

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Posted by 93PONY (Member # 60) on :
 
Comp XE270HR on a 112LSA
or the XE274HR will both make good power.
But, if you're going to order directly from Comp, I'd suggest just getting a custom. There is no difference in price.

For your combo I think this would work well:
224/228 110LSA .555/.536 w 1.6's .590/.570 w/1.7's. Installed on a 110ICL (straight up).
Good valvesprings would be needed. 125-135lbs seat. (This cam would not pass somg) If you want a little more midrange grunt, have it ground with a 109LSA & intall it on a 109ICL.

If you want the Comp lobe part #'s for ordering this custom, let me know.

-Shaun
 

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Posted by LX Pony (Member # 2216) on :
 
Thanks alot Shaun, I'll definitely let you know. Any idea how that cam would idle or what driveability would be like? I might be cutting it a little close PV clearance wise, but it might clear. I do have dual springs and quality locks and retainers though. Where do you think it would make peak HP, and when do you think it would come on?
 

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Posted by 93PONY (Member # 60) on :
 
Idle shouldn't be a problem. A little lopey, but nothing big.
You'll definately have to check P to V, but it'll probably clear. GT40's have small valves that fit in the stock valve reliefs.
Peak power will probably be in the 5800 range.
It'll pull from ~2800 to Redline.

If the springs aren't up to the task, you'll get severe valve float & lose a good chunk of power up top.
 

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