[johnta1]

I'd check all the things you changed, instead of what was there already for problems?

The Strange S60 Rear end like the Dana60 rear end?
If so that is a real heavy rear and possibly uses more HP to use it?
You don't have that much HP to give up I think.

The higher gear probably makes the converter act like a lot lower stall converter? Try a higher stall converter?

Is the new rear and other chassis stuff set up properly?

Try spinning the rear with it jacked up and see how hard it is to rotate?

[Half-Inch Stud]

...throttle not opening all the way is a classic fix. Check it?

[ebartone]

Originally Posted by Half-Inch Stud

...throttle not opening all the way is a classic fix. Check it?

Thank you for saying this! That’s actually something I checked about a week ago, it had crossed my mind. Like I said, towards the end of the track I feel like there should be more and it’s holding back. Throttle plates not opening up all the way, definitely crossed my mind and I recruited the wife to hold her foot down while I double checked, thank you! I’m also swapping out the air cleaner just for grins to see what happens.

Whoever said it made a good point, what is it that changed since last season, rather than issues that would have been there before as well. It does occur to me that the air filter that I was using, late fall after I put her away, I cleaned it out, then oiled her up pretty good. Maybe I over oiled and it’s already clogged up, I don’t know, but Ill find out.

[Steve C.]

A fwiw.....

I'm not sure if it's brand specific, but related to testing a K&N X-Stream filter lid with a q-jet carburetor. Years ago when I spoke with a K&N Tech Rep he supported comments made within in an article that the entrance on a Holley 'HP' series carb with its smooth contour does in fact act like their Stub Stack and will help it work with the X-Stream lid. Whereas apparently a Holley carb design without a smooth contour (w/ choke tower) and like a Q-jet doesn't work as well with a X-Stream lid.


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[b-man]

Just take off the air cleaner, or at least remove the filter and the top leaving the base in place (secure it) and see how it runs. No money spent.

3.70 should be a good gear, you have other issues. It’s not like you went nuts and put 4.88s in it.

Fuel delivery even with the big 550 mechanical pump may be an issue, especially if you have not yet upgraded the fuel line from the tank to 1/2”. Keep your tank at least half full. You really need to hook up a fuel pressure gauge even just temporarily on the cowl where you can see it.

[Steve C.]

Sort of related....

Out of interest I talked with a tech rep at K&N about the air flow requirements for my 505cid engine and if the small air cleaner assy I was using is adequate. According to their formula a 505 cubic inch engine at 6000 rpm requires about 745 cfm of air flow. Because of hood clearance issues I'm using a 'small' 9-inch diameter K&N filter assy with the K&N X-Stream filter lid. According to him both used together will support about 650 cfm. So he said on the street I'm fine. If I went to the track I'd just remove it. The was with the cut down Victor intake and my custom HP950 carb.

When I changed to the direct port fuel injection I put the car on a Mustang chassis dyno for interest. To the wheels it made 591 hp at 6000 rpm with the filter assy in place.
Removing the filter assy it made 608/609 hp at the same 6000 rpm. The 18 hp difference on the street is a moot point !


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[JLBIII]

I was having problems towards the end of the 1/4 mile running a RobMc and Qjet. It felt like it was starving for fuel. Switched over to an 850 dp. Had the same issues. Took the car over to the dyno shop. On the dyno the tech found an ignition problem around 5400rpm where the module was starting to cut out. We replaced the old distributor with a new MSD. The problem went away and the engine now makes power up to 6300rpm. The ignition might be something else to check.

[GOAT8U2]

IMO, put an AFR gauge in it and know for sure since you track it.