I have made a few changes to the wife's car over the winter, and before we really started thrashing on it for the season, I wanted to make sure the A/F and timing we all top notch. We dyno tune all of our vehicles, and we spend a lot of time tuning the entire range, not just WOT. That said, results are in, and it seems my butt-dyno is just as accurate as ever, as I had estimated 140rwhp before we started. I'll post a picture tomorrow of the full graph. We realized with 2-3" of vacuum starting at 2600 rpms that the car was grossly under carburated with the 2bbl Holley. Luckily we have an Offy 4bbl intake going on the car soon.
Final results:
137whp/175wtq





Her build:

Super 6 2bbl(aluminium)/Holley
Clifford Headers (3 to 1)x2
Ported Heads/ Oversized valves
Comp 264/264 Cam
Decked block for 9:1 Comp

PB904
2.76 geared 8.75
26" tire

So my question is this, I know the HP should come up pretty significantly with the 4bbl, however, I'd like to see something closer to the 225wtq/185whp area. I'll be speaking with my cam guy tomorrow to see if this is possible or if I'm shooting for too lofty of a goal without putting a huffer on this thing or what. Any suggestions?

I would say more cam and compression should reach that goal pretty easily along with the 4bbl

Kev

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I have a shaved head that is ported and valved the same as this one. However, we had to run 100 just to drive it around town and 110 at events. Wife says no more race gas, lol. We have it on the pump here, but 8 bucks a gallon gets a bit nuts.

50 ft/lbs is a 28.5% torque increase. I don't see that happening without forced induction. You can get the horsepower up where you want, but it's going to take more cam, carb and compression.

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Joshua

You think the head is so restrictive we can't get 1ft/lb rwtq per cubic inch?

I was reading the "build matrix thread" and I've deemed it pretty subjective. I find it hard to believe no one has hard dyno numbers for their cars...

You have not put the 4bbl on yet, correct?

When I changed my Duster from a Super Six BBD to an Offy and 390 Holley it picked up over 1/2 second.

A BBD is an improvment over a 1bbl, but it is still a cork in the sytem, especially with a ported head and big valves.

Also, if you are on a chassis dyno your numbers are already 15-18% lower than an engine dyno.

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Official Cookie and Mater Tormentor.

Dan-o I'm definitely interested to see how your upgrade to a 4bbl works out.
I'm running a similar setup to you and I recently got 138 rwhp and 160 rwtorque.

I think I can get more out of it the timing wasn't right and I had overheating issues so had to shut down prematurely

I'm currently running a 2bbl 500 holley but would like to see what a 600 4bbl would do.

Love to see your dyno graph

Good luck with it

PS what was your AFR reading?

Cheers

If you had more cam it would lower your dynamic compression which would allow you to run lower octane fuel. My previous NA motor used an erson cam 238@.50 duration 108lsa 510 lift with slightly over 10:1 compression ran on pump gas everyday as a daily driver. Your 264 comp cam is a pretty mild cam which would cause you to run into those ping problems when raising the compression.

Kev

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Dyno testing costs money and isn't available in a lot of places. More of us go to the drag strip. I can't tell you what the horsepower and torque changes were, but I improved my '67 Valiant from a best of 19.2 to a 16.9 in the 1/4 mile with head, intake and exhaust work. No cam change, no bottom end work. Real numbers, but not the one's you're looking for.

Stock engines of our vintage make about 1 ft/lb per cubic inch, gross. Even 4-valve engines do little better. The 225 is rated 145hp and 215 ft/lbs. You're getting close with the hp with your modifications, but a nearly 30% torque increase when the low hanging fruit has already been picked?

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Joshua

I'm interested to see the results as well. 3 inches of vacuum is a pretty significant bottleneck; and a half second at the track is nothing to sneeze at either.

I have dynoed an engine similar to what you are contemplating. With 10:1 compression, ported big valve head, a Holley 500 2bbl on an Offy manifold, Clifford shorty headers, and a Racer Brown ST-22 cam, similar to a Mopar Performance 276 it made 215RWHP. That was with a standard transmission, drag strip times indicate about 240HP at the flywheel. I have also tried a 525CFM 4 barrel and noted no improvement. This engine runs fine on pump premium but I splash in some racing gas at the strip just in case it needs it. If you really want 240 RWHP in a streetable combination I think you need to think boost or a light nitrous shot.

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If you didn't drive it there, it's not a street car.

Cool, sounds like it may be doable. As we autocross and cruise this car, I'm more focused on a "squared" motor. When I build my V-8's for performance duty, I like to see a squared motor, with 1hp and 1ft/lb per cid at the rear wheels. With the rod stroke ratio we have with the tall deck slants, I figured 1 ft/lb per cid to the rear wheels with .82 of that number in hp should make for a good little motor.
I think that as of now, 240rwhp would be a bit much for my wife, as we have the car fairly over tired and under powered, so it's really hard to overdrive the car. As her skill set improves, we'll be looking to do the cam swap, probably over the summer.

The big problem with 225's is the head, it's too restrictive for the bottom end.
Maybe see if you can do a little more work to the head to get it flowing better before tearing into the bottom end?

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1965 Plymouth Belvedere II Turbo Project - SOLD
2002 Subaru OBS
1995 Lexus LS400 Race Car

Explain to me why a 264 cam is milder than a 238? Are these different things being measured? Is the 264 not measured at .050 as well? Thanks.
Sam

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Sam, the Comp Cams 264S is advertised duration (usually, but not always .008" tappet rise) and is 220° @ .050" tappet rise.

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Joshua