E85 4150 tunnel ram tuning

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Sounds like it has alky type metering blocks. I only use those on something that needs alot of fuel flow.

[HarrysTaxi2]

[2x4b4fun]

On the first page jmarkaudio suggests getting some .020 e bleeds. Anything smaller requires set screw blanks and drilling your own. They can be purchased from BLP. Installing these and going to a 24-25 HSAB will help flatten things out and possibly make the carbs work better with the large cross channel and overly large (850 size) booster. It is possible to get them to work just not as well if everything was sized properly. From all that I have sourced from different forums 750 like cross channels in the 150-160 range and boosters 160-166. As I stated earlier I used 154-155 cross channels and 158-159 boosters(stock) and got good results. With the large booster you have I would guess 95-99 jets would be needed. Some specs others have posted show a 750 with a 170 booster needing 95-96 jets. Here's a copy from a few years ago on another forum talking about emulsion;



I played with emulsion on my 4150 carbs, and found that .014" and .016" work very well with E85.

My Dominator prefers .018" and .020".

With the 4150, the emulsion stack looked like this: blank / .014" / blank / .014" / blank.

With the Dominator, the emulsion stack looks like this: .018" / blank / .018" / blank / .020". The performance did not go through the roof, but it tightened up the consistency, and jetting was a lot easier to dial in.

I would suspect in this particular case with the big block and normal plenum volume, that .018" in 2 and 4 with 1 and 3 blank would work well to start.

Also, I would recommend that if you are not using a power valve, install blanks in the PVCRs. This isolates the mainwells from one another.



If your currrent blocks are for Alky you may have another problem if they have divorced idle. This tidbit also came from jmarkaudio and explained why I was having problems getting things to work. My 4150 alky blocks worked finally after drilling new idle feeds and blocking the bowl ports on my 4500 but cross channels were too large still when I reduced the banjo sizes so I started over with new blocks.

[Right hand drive]

Found this for reference

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