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Discussion Starter · #1 ·
It's been mentioned by a few people that there is a possibility that my cam is not enough for my 3700 converter.
I filled out the online cam help for on Comp Cams website and gave them detailed info about my setup.
They said my 274XE cam is too not enough and I should step up to the 294XE cam.

The specs are 294*/306* .554/.558

What do you guys think?

_________________
1982 GT
351w(.060), ported & polished heads with 1.94/1.60 valves, 10.3 comp, stealth intake, 274XE cam, Holley 750 dp, Mallory dist., shorty headers, flowmasters, 4:10 gear, c-4 with 3700 stall converter, subframes, electric fan

<font size=-1>[ This Message was edited by: 82GT on 8/8/06 10:30am ]</font>
 

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what year head is that? Comp cams tech guys are made up of 9dollar an hour guys following a set of guidelines. There are a few there that know a good deal, most are just picking. What does that head flow, particularly the low and mid lift numbers?
 

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With the 750 carb and stealth intake I think that cam is the right size. Why are you asking? Are you looking for more power, or rpm or...?
 

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Discussion Starter · #4 ·
Woody, my heads are D4 heads that have been mildly ported & polished with oversized 1.94/1.60 valves installed. I have NO idea what the flow numbers are.

OU812, I'm asking because I've heard a quite a few times now that my cam isn't enough anymore since I went from a 2400 stall converter to a 3700 stall. This 274XE cam is about out of steam at around 6K
So yeah, I guess I'm looking for more rpms.
You gotta admit that my cam is a bit on the mild side. (274/286 .519/.523 110*LSA)


The new converter knocked almost 3 tenths off my 1/8 mile times but still runs the same 13.3's as before......with 6mph LESS trap speed.
I'm going racing Friday night and it's supposed to be much cooler than last time I ran.
If my trap spped is not up to the 104+ it used to be last summer, then I'm going to have to step back and re-think my setup. I know better heads would work wonders but they are not in the budget right now.
I feel this setup should still run a little better than what it does.

<font size=-1>[ This Message was edited by: 82GT on 8/8/06 10:38am ]</font>
 

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I think you have a bit too much converter, everything else is a pretty decent match

If you go bigger cam, you really need to build around it
 

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Discussion Starter · #6 ·
On 2006-08-07 19:56, My427stang wrote:
I think you have a bit too much converter, everything else is a pretty decent match

If you go bigger cam, you really need to build around it
That's why people are saying my cam isn't enough anymore because of the converter.
Shouldn't I change the cam in order to match the converter again?
 

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Converter is fine, but sounds like the engine is laying flat after the 1/8 mile...could be not enough fuel. After 3700 rpm, the converter is basically locked up, so it should not affect high rpm.
But now your leaving the line harder, which puts a huge demand on the fuel system.
If you et better, even in the 1/8 but dont gain mph, its usually fuel system.
Brian
 

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Discussion Starter · #8 ·
Yeah, I was thinking fuel system too. I don't know which way to go....new cam or new fuel pump and ditch the holley blue.
I have -8AN fuel line and sumped tank with a 110gph holley blue for my fuel system. If it IS a fuel problem...it almost HAS to be the pump.
I did put rear jet extensions since the last time to the track but haven't run again since then though but I don't think extensions help anymore after the 1/8 mile.
 

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a set of heads might be a good starting point.i run that cam with a 2800 convertor,changed from ported 69 351w heads to rpm heads and the difference was like night and day,still a street engine that will go to 6500rpm no problem.im no expert but dont you think youll need a better set of heads to take advantage of a bigger cam like the xe294.

<font size=-1>[ This Message was edited by: steharz on 8/8/06 1:42pm ]</font>
 

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If it's working correctly, the Holley Blue should supply enough fuel. I think I'd invest in a fuel pressure guage before ditching the pump.

If you change to a larger cam you should also raise the static compression ratio.

See

Dynamic Compression
Program and explanation of Dynamic Compression
http://cochise.uia.net/pkelley2/DynamicCR.html

Compression Comprehension
You can run 11:1 or even 12:1 compression on your pump-gas street motor, but you'll need this simple advice to make it happen. By David Vizard
http://popularhotrodding.com/enginemasters/articles/hardcore/0606em_understanding_compression_ratio/
 

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Discussion Starter · #11 ·
Then where is the 6mph that I lost.......hot weather?
 

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The XE274 is a good cam for your combo.Going to a bigger cam with those heads isn't going to do much and might even slow the car down. If all that was changed was the converter my guess is it is slipping causing the MPH loss. Your time slips will probably show improved 60 foots due to the converter allowing the car to leave harder but loss of MPH because the converter is slipping. I'd change the converter before changing the cam.
 

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What kind of RPM are you shifting at? going over the line at? I would agree a fuel system upgrade may be a good idea and Comp Cams may be right, you definetly can have to big of convertor for a milder cam and have it run of of steam because of to much slipage/not enough upper rpm a$$.
 

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If you lost 6mph and all you did was change the converter, then I think you have your answer as to where the loss of 6mph came from.
 

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You gained MPH in the 1/8 with the converter switch because now the motor can SPIN up to the 3700 RPM faster than it did before.

You lost MPH in the 1/4 with the conveter switch because now the motor spun up at lot faster to 3700 RPM and you are past your torque peak meaning that it has to continue to accelerate you through the rest of the track with less power.

Or not
... but as I always like to say....I'm no expert.

You had a 2800....then you went to a 3700....maybe its time for something in the middle.


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65FB 408c AOD D.T.



<font size=-1>[ This Message was edited by: dodgestang on 8/9/06 2:23am ]</font>
 

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I agree with the others the cam you have is a pretty good match for your combo..If your looking for bottlenecks try the heads,shorty headers and stealth intake...I don't think there is any point in going to the big cam while you are running these parts.
 

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Discussion Starter · #17 ·
If the converter is INDEED too much now then I would rather build around the converter. If I need more upper RMP then I would rather change the cam or heads or BOTH to get there instead of swapping converters..AGAIN

defree383.....I'm crossing the traps at around 5200-5300 rpms and I DO have an ugraded fuel system(Holley Blue, -8AN fuel line, sumped tank, jet extensions......) what more can I do to the system?

It WAS hot and humid day the last time I ran so that might have played a role in the MPH loss. I'm going to Friday night where the weather will be much cooler.
 

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I've had problems with holley pumps in the past, personaly I wouldn't run one, they are a little weak when you start going fast. It may or may not be a problem for you yet. but think about looking into a better pump.

How much fuel are you running in your tank? you can still have sloshing problems with a sump if you running it to low.

Who's convertor are you running? Please tell me its not a midnight special? is it truly stalling at 3700? or is that just the mfg rated stall? whats the diameter of it?

What was your old convertor? rpm at finish line? Could you post some before and after time slips if you have them?

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1991 LX Mustang 347 C4 combo 11's with the AC on.
1984 Mustang GT 460, Powerglide "Still putting it together" hoping for 9's !!
1929 T-Altered "In the works" 8's are on the horizon

<font size=-1>[ This Message was edited by: dfree383 on 8/9/06 4:37am ]</font>

<font size=-1>[ This Message was edited by: dfree383 on 8/9/06 4:39am ]</font>

<font size=-1>[ This Message was edited by: dfree383 on 8/9/06 4:40am ]</font>
 

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Discussion Starter · #19 ·
No "midnight special converter" here. It's an Edge converter that's 9.5inches. If you know Edge converters, you KNOW that they are truely custom built to order.
My old converter was an TCI 2500 stall(12 inch). It was JUNK and acted just like a stock one. My new one DOES flash to 3700.
I'll have to look up my old tiime slips.
 

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I duuno seems weird to me.

Converter $200-$1000

or

Cam/lifters/springs/retainers $300-500
Heads - $800-$2,000?

I'm sure someone, somewhere, sometime (and it might have been me) asked...so what is:

Use for the car?
The performance goal?
The budget?

Seems like a lot of effort to me to basically re-think the entire motor build for the sake of using a converter.

My old converter was an TCI 2500 stall(12 inch). It was JUNK and acted just like a stock one. My new one DOES flash to 3700.
I'll have to look up my old tiime slips.
And this would be the old junk converter that you ran faster times in the 1/4 in but had slower 60 foots with?


Since you seem to have the money available, why don't you spend $500 and a few hours with a good dyno tech, get the full work up. You may find out that you just aren't quite tuned to where you should be.

FWIW - as I understand converters, if you change the cam, heads, intake etc on the motor, you will be changing the power characteristics, thereby also changing the stall the converter will flash to, so in essence if you change all the parts of the car you won't know what the converter you have now will flash to until after its built.

<font size=-1>[ This Message was edited by: dodgestang on 8/9/06 9:33am ]</font>
 
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