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 Post subject: 950 T-slot
 Post Posted: Wed May 16, 2012 4:04 am 
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Location: Central Oregon
I got to messing with a hp950 I have and noticed the t-slot is larger than a .110" drill bit! If we're restricting out dominators to .055" or so wouldn't it make sense to do the same with this carb? This carb is fairly rich all the way around on my combo and it seems in line with the rest of the mods on this carb, IFR reduction, main jet and MAB reduction etc. Just looking for some opinions or info if the 4150 and 4500 are similar in that respect.
Thanks

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 Post subject: Re: 950 T-slot
 Post Posted: Wed May 16, 2012 7:59 am 
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While I don't ever remember reading where TSJs have been installed in a 4150 carb, I see no reason why they wouldn't work with them the same as they do with a 4500?? :-k Keep in mind though that this is "opinion" and not based on personal experience and as usual, your mileage may vary.

So having said that, I'd wait for more input from others before you go "molesting" that carb. ;-)

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 Post subject: Re: 950 T-slot
 Post Posted: Wed May 16, 2012 9:12 am 
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The passage in the main body isn't the reason for t-slot jets, it is the area of the slot itself. On a 4150 the slot is in the baseplate and usually sized correctly. A Dominator had slots that were too low or too high and usually too long. Too low has it's own issues, too high can be corrected by making it longer but that gives it even more area. That is the reason for a t-slot jet, that restriction is placed in the mainbody on a Dominator. The ideal fix is what BLP does, they drill it out and machine a plug to fit with a smaller slot in it, but you can usually make it work well enough with the t-slot jet and calibrating to suit each carb. Unless the slot in your 4150 is more than around .250 long I would not expect you need any restriction.


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 Post subject: Re: 950 T-slot
 Post Posted: Wed May 16, 2012 10:53 am 
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All this time and I never heard this about the slot? I mean I knew that the slots weren't in the correct place sometimes but never associated the area as a problem also. So all this actually comes down to the area of the slot being too large and using the TSJ as the restriction rather than the slot itself. :-k

This being the case, then I would somewhat question the "one size fits all" thingie as no two engines will be exactly the same. So I guess then it comes down to the actual T slots in any Holley carb being made large enough that the IAB can be used for fine tuning rather than the TSJ. :-k

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 Post subject: Re: 950 T-slot
 Post Posted: Wed May 16, 2012 12:57 pm 
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Thanks you guys. Mark, that's exactly what I was looking for as I wasn't sure about the 4150 but of course now I need go back to my 1050 and do some measuring. Knowledge is power, HORSEPOWER!

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 Post subject: Re: 950 T-slot
 Post Posted: Wed May 16, 2012 1:03 pm 
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F636 wrote:
Thanks you guys. Mark, that's exactly what I was looking for as I wasn't sure about the 4150 but of course now I need go back to my 1050 and do some measuring. Knowledge is power, HORSEPOWER!


Well, I don't think there's any power in T slot tuning but it will make for a smoother running engine at part throttle! ;-)

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 Post subject: Re: 950 T-slot
 Post Posted: Wed Jul 04, 2012 9:08 am 
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F636 wrote:
I got to messing with a hp950 I have and noticed the t-slot is larger than a .110" drill bit! If we're restricting out dominators to .055" or so wouldn't it make sense to do the same with this carb? This carb is fairly rich all the way around on my combo and it seems in line with the rest of the mods on this carb, IFR reduction, main jet and MAB reduction etc. Just looking for some opinions or info if the 4150 and 4500 are similar in that respect.
Thanks


Out of the box my 950HP was ridiculously rich on the idle and transition circuits and lean at WOT. This is on a warmed over Ford 460 in a street car. After much trial and error changing bleeds, jets, e hole configurations, and every possible butterfly to t-slot adjustment etc... a .063 t-slot jet ultimately solved the problem. When I was done the calibration bore a very close resemblance to the "crispy" recipe that so many of the "new era" carbs seem to end up at to run well. Go figure.


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 Post subject: Re: 950 T-slot
 Post Posted: Wed Jul 04, 2012 11:49 am 
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That's what it seems like,trial and error, Mark and others here can get you close but it's up to you to get it where it's right for your combination ;-) ..

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