thanks,

James

I suspect that the loose converter may indeed be your problem but,.....are you certain that it is a 5500 RPM converter or are you going by what someone says it is or was? Have you ever performed a stall test? Does the car have a trans brake?
If the motor gives up at 6k and you really have a 5500 converter you would not be able to notice the shifts. It would act as if it has a one speed.

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Alex Denysenko
Co-Administrator and Moderator

NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl

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Alex Denysenko
Co-Administrator and Moderator

NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl

------------------
Alex Denysenko
Co-Administrator and Moderator

NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl

The convertor is probably too loose. But there may be something else not right in the combo.

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Rob Hetzler
member #773
'69 mustang, 351C, best 9.97 @ 133 mph 1/4, 6.18 @ 109.9 1/8, 1.319 60'
'70 mustang, flintstone power
'93 F150 Lightning 15.33 @ 87 mph, completely stock with 164k miles
'99 Pro Et track champion
'00 Mod ET R-up (with new car)
'01 5th place Top ET, 7th place Mod ET

quote:

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Originally posted by Warhorse:
heads are stock 289's with 351 valves. The car feals pretty sluggish and after 6000 rpms it does not pull anymore.

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Those heads (unless properly ported to the water jackets) won't support that rpm range. Stock heads won't make anything but noise over 5000 rpm, regardless of what's bolted to the rest of the engine. The 351W valves will only hurt things unless the bowls have been opened up to match, and the chambers have been unshrouded.

If you've got the huge cam and matching converter, INSTALL AN AFTERMARKET SET OF HEADS, AND HOLD ON!

The car will be a 'turd' with stock heads in that setup. You might get the car to do burnouts, and possibly get it into the 7's (1/8 mile) with a smaller cam and tighter converter.... but you'll end up spending close to the same amount of money as you would on a good set of cylinder heads.

Good aftermarket heads will do more for power production than any other modification that can be made. Even ported, they have their limits, and aren't ideal for any engine combination designed to run over 6k rpm. It's hard to say how fast Alex's car would run all optimized with a modern set of heads and a big carb.

If you aren't married to those heads, give them the 'boot'. Trust me, you'll be THRILLED with the horsepower increase.

This is coming from someone who knows what it takes to make a set of 289 heads work. see sig, below

Good Luck!

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Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/carbedstangs/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367
http://www.mustangworks.com/cgi-bin/moi-display.cgi?220

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65 mustang
drag car, 302, Elderbrok aluminom intake, Holley 4-barrel, Comp cams .592 lift, 289 heads w/ 351 valves, longtube headers, narrowed 9 in. rearend w/ 5.86 gear, 31 spline axles c-4, ladder bar suspension, 31x13x15 slicks, 6 point cage

"If you are running stock 289 heads with 351W valves with a large by huge cam that requires a really loose converter... that's the main problem.The car will be a 'turd' with stock heads in that setup. You might get the car to do burnouts, and possibly get it into the 7's (1/8 mile) with a smaller cam and tighter
converter."

I had a very similar setup..289,351w heads, 12.5 trw's,and a big lift long duration cam(not quite as big as yours).I also had a 4000 stall and it was a DOG off the line.It would barely do a burn-out when I got up on the converter(back end would lift and the car would make a whole lot of noise but thats about it)I took the big cam out, went to a smaller cam (230@050/520 lift)and the combo really woke up.lights 'em up fine and doesnt go flat at the top end.just my personal experience.

quote:

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Originally posted by Warhorse:
The pistons are pop ups with 12.5 compresion. If I went with a set of alluminom heads what size valves could I go with before I would have to start grinding on the pistons? Would this help my problem or would I still have to change the convertor?

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More specific engine specs would be appreciated... Carb number or cfm? Intake? Cam 0.050" numbers?

Aftermarket heads will help big time.

You didn't give the 0.050" numbers on the cam, but I'm assuming it should be plenty big enough to turn around 7k rpm in a 302....

Is the 5500 rpm stall figure an 'advertised' number, or is it what it actually footbrakes to?

If it's actually footbraking to 5500 rpm with your existing engine, I'd say it's on the loose side... and may even be ballooned out or damaged, unless it was custom built to be WAY loose. If it just footbrakes around 4-4.5k rpm with that engine, it should be fine.

The engine isn't going to make much power 'upstairs' until a nice set of aftermarket heads are perched on top of it. Combine a quality set of heads with a Holley double pumper, Victor Jr. intake, and a solid lifter cam... and you're in the horsepower business!

If the engine just has a smallish carb and dual plane (or small single plane) intake, and you don't want to make much of an investment, go for a smaller (230-ish @ 0.050") cam and tighter (4-4.5k rpm) converter. If it has a big carb and Vic Jr. intake, go with the heads.

As for needing to check for valve clearance with the aftermarket heads and domed pistons... It may be required. However, those 12.5 TRW's have larger valve reliefs than their 'generic' forged flat tops. If they need a little clearancing, just do it with a die grinder. The reliefs should be deep enough, they just might need widened out a bit for the larger valves.

Good Luck!

------------------
Alex Denysenko
Co-Administrator and Moderator

NHRA/IHRA/SRA member and licensed Superstock driver
MCA member# 53321
NHRA and IHRA SS/LA National Record Holder '00, '01, & '02
Fleet of FoMoCo products including 88 ASC McLaren Mustang #28
Professional Manwhore
The Barry of BarrysGrrl

As for the rest of the engine, the carb should be upped to a 750 double pumper, and the Victor Jr. is a great move.

I know you want to avoid opening up the valve reliefs on the pistons, but those Edelbrock Performer 1.94 heads are still a bit undersized for that combination. Although more expensive, a set of Airflow Research 185's would be a GREAT 'bolt on and go' head for that combo. If you buy direct from AFR, they can set them up for you cam right from the factory.

You can either go with the above 'wild' combo, or move toward a slightly milder, more reliable setup that will be able to re-use your existing carb and intake. However, you'll need a smaller cam, tighter (4500 rpm stall) converter, and better heads. You might be able to get by with the Edelbrock units, or even go with the 185's. A solid cam should measure around 236 @ 0.050" on the intake for this milder combo, and the engine will be shifted around 6500 rpm.

The top (high rpm) combo will require more maintenance, will go faster, but won't last as long... and the bottom setup will still be way faster than the current one, be more reliable, and will live longer.

Regardless, lose the stock heads... and be sure to check piston to valve clearance, and have the rocker arm geometry checked.

Good Luck!

James