Howdy

My new 408 street machine combo is going to the chassis dyno on weds. It's a mustang dyno at buddy's shop. He's a tig welding fabricator and import turbo fuel injection whiz which is awesome but not my thing. Two valve per cylinder carbureted naturally aspirated pushrod engines are not his thing! He's hooking me up with a friend price for dyno time but I'm doing all the tuning.

This is not my first rodeo wideband tuning holleys or 408s but I want to have a solid strategy to get results fast. I want to a good street tune that won't foul plugs with good WOT power. I'm running a 750DP with an HP main body. It's got adjustable bleeds but the IFR gets leaned out with wire and the PVCR is also not a screw in. Luckily the IFR is the low style below fuel level. The emulsion bleeds are also not replacable jets on my set up.

I'm thinking I will get on the rollers and warm up, then ballpark the four corner idle on the wideband. Next will be trying to simulate a low throttle 35mph cruise on the T-slots. If it is close I will try idle air bleeds to sharpen it up, if not then work with the IFRs first. Once that's done the idle corners and curb idle rpm can get finalized.

Next on to the primaries- I'm not sure if I'll try and put slack in the throttle to just open the front 1/2 of the carb? I know a 60mph cruise is solidly into the primaries. Anyway, my PVCRs are not currently adjustable so I figure I should see how much richer the power valve gets it then jet for a compromize between best power with PV open and leanest clean cruise with the PV closed.

I'm planning to run the secondary with no PV so it should be relatively easy to jet for best WOT power from say 3000-6200 with just the secondary mains without touching any of the other circuits that have already been set.

My acc. pumps have smallish nozzles and pink? cams in them from my last 408 combo- the old airgap certainly needed less fuel so I'll probably have to go bigger. I have a complete set of jets and air bleeds and pump cams but only a handful of random squirters. Is this even something worth messing with on the dyno? Seems like I might be better off doing the pump shot last- I always did it seat of the pants until there was no hesitation.

I am planning on leaning on the experience of others with the timing. I'm thinking my current setup should be safe on high test pump gas. I am planning to try going to 36° total to see if I get more power. Does it make sense to take for granted that 34° is close enough to do the AFR tuning first, then try a little distributor twisting? It's 10.2:1 CR with basically stock edelbrock chambers and .040" quench.

I don't want to waste my friend's valuable time (or my own) or beat the car with endless runs. I probably won't be getting crazy scientific calculating jet areas or A-B-Aing the changes. I just want to work methodically and intelligently toward my goals and leave knowing I didn't leave much power on the table.

Thanks for any comments experience or advise.
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