408 tuning with a Wideband sensor

-
Thanks for the vote of confidence. This could prove to be some good info if I manage to stay on task.
 
I doubt the 750 metering block has a big enough IFR to stuff .023 wire in it.

Pin gauge the IFR size and if it's larger than about .030 find a piece of wire to reduce the area to the .028-.030 range. that should lean out your cruise a little bit.

The IFR's can be at the top or bottom of the channels.

http://members.tccoa.com/392bird/carbtech.htm
 
I'd like to drill out the IFR's and tap them for a 10-32 set screw. Then I can easliy make any size that I want and swap them in. I'm assuming that this needs to be done to the secondary metering block as well?
 
I've also heard of guys switching to a Proform main body. This would be one way to get adjustable air bleeds. Not horribly expensive at $125
 
The main body is a nice change.

I forget, I think I did 6-32 or 8-32 for the IFR's because they usually aren't that large orfice wise.

You could tap the main body you have now for adjustable air bleeds.
 
Good point. Would it be worth it to do the high speed bleeds as well? Do you happen to know the thread size?
 
I decided to go with the Proform main body. The mod to the one that I have would be simple but I like the fact that the Proform gets rid of the choke horn. I never use the choke anyways. If anyone is looking for a manual choke main body for a Holley DP I'll let it go pretty cheap.
 
Loosenutz said:
I decided to go with the Proform main body. The mod to the one that I have would be simple but I like the fact that the Proform gets rid of the choke horn. I never use the choke anyways. If anyone is looking for a manual choke main body for a Holley DP I'll let it go pretty cheap.
Click to expand...

Where did you get the Proform at and What was the $$$ ??
 
Mine has the choke horn too. I may do the same after I get my POS Running again! Should be firing it off hopefully on Wed night.
 
Loosenutz said:
Let me know if you're gonna make it to Grand. I may meet you there.
Click to expand...

I'm gunna try for sure. At this point I am at the mercy of UPS and Fedex! They both re routed parts last week and they get here on Wed. So Wed start up, Thursday work out the bugs if any.
 
Proform main body arrived today. Should be able to get it swapped in tomorrow night so I can get back to the tuning. I'm going to start with the jets included in the Proform kit. Comes with 72/84 for the mains and 36/73 for the air bleeds. I'll also switch back to the stock 6.5PV from the Holley. It will be interesting to see how it performs right out of the box.

20130603_130850.jpg
 
HAHA! Yeah, that's quite the claim they are making. I'm sure some gain is to be had with increased airflow but 25HP!! I've heard they're great pieces though.
 
Loosenutz said:
HAHA! Yeah, that's quite the claim they are making. I'm sure some gain is to be had with increased airflow but 25HP!! I've heard they're great pieces though.
Click to expand...

Haha yeah kinda funny. It looks sweet for sure. I just checked on the one for my 850, it is about $70.00 more for some odd reason. I wonder if I could just run the same one you got? I don't see why not?
 
It should. Says it flows up to 870CFM and fits all 650, 750, 850 DP with mechanical secondarys.
 
Pulled the carb off so I can swap in the new body at work tomorrow. Was tempted to do it at home tonight but I just cleaned my condo and don't want it stinking of gas for a month. I also need to get some carb studs tomorrow. The bolts were supposed to be temporary...

20130603_195233.jpg
 
Carb body swap was so easy I could have done it in the dark. Fit and finish was great. Hopefully the tuning goes just as well.

20130604_165437.jpg
 
Did you pin gauge the IFR's?

If it runs rich on lower speed cruise before the mains activate, you may need to reduce your IFR's. Some stainless wire will do the trick most of the time on non adjustable metering blocks.
 
No I didn't check. I swapped to this body so I could increase the air bleeds if I need to lean it out.
 
You must log in or register to reply here.
-

Back
Top