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Search found 3791 matches

by jmarkaudio
Mon Jan 13, 2020 11:33 am
Forum: Engine Tech
Topic: 4150 4778 Holley carb questions
Replies: 12
Views: 532

Re: 4150 4778 Holley carb questions

The two biggest things would be to make the idle air bleeds adjustable and the PVCR's. You will need a good selection of drills and a couple bottoming taps.
by jmarkaudio
Sat Jan 11, 2020 12:26 pm
Forum: Engine Tech
Topic: Any experience w/ Braswell 14"-15" tapered air cleaner?
Replies: 12
Views: 467

Re: Any experience w/ Braswell 14"-15" tapered air cleaner?

I have adaptor rings that will fit the 4825 and allow a Dominator air cleaner if that would work... We use them on the large oval blade and BLP Extreme bodies.
by jmarkaudio
Tue Dec 24, 2019 11:50 am
Forum: Engine Tech
Topic: HRM history of the SBC omitted the 400"?
Replies: 60
Views: 4492

Re: HRM history of the SBC omitted the 400"?

Between my dad, brother, and myself we went thru a lot of 400's over the years. 1970 had a shallow dish, the most compression from the factory that I ever saw or read about. 71 on had a deeper dish. A lot of our early bracket combinations used a forged TRW version of that shallow dish piston, using ...
by jmarkaudio
Mon Oct 21, 2019 12:59 pm
Forum: Engine Tech
Topic: Block choice for SB2 heads
Replies: 10
Views: 686

Re: Block choice for SB2 heads

You can use a block with standard lifter bore spacing bore with the SB2.2 offset. The SB2.2 offset is ideal, you will have less potential issues. Standard bore loads the lifters a little harder, we have seen broken tie bars with them. Dart can custom bore for the SB2.2 offset, my 9.5" deck aluminum ...
by jmarkaudio
Mon Sep 30, 2019 1:17 pm
Forum: Engine Tech
Topic: Bigger Carb?
Replies: 7
Views: 991

Re: Bigger Carb?

Do you have any restrictions on what carb you can use? There are options with sizes using a billet body, I would look at something in the 1.40-1.45 Venturi range with a 1.75 throttle blade. If you are looking to go cheaper than new either a QF 850 or 950 will get you there, the 850 is 1.40 Venturi, ...
by jmarkaudio
Thu Aug 22, 2019 11:08 pm
Forum: Engine Tech
Topic: Gen 3 950 dominator
Replies: 36
Views: 1509

Re: Gen 3 950 dominator

The t-slot restrictions as delivered on the one I reworked were at .063. A little larger than I would like but probably OK to start with. They don't need much, lower the idle feed, recalibrate emulsion, and a main and idle air bleed change. From there jet as needed. I'll message my number, give me a...
by jmarkaudio
Thu Aug 22, 2019 9:42 am
Forum: Engine Tech
Topic: Gen 3 950 dominator
Replies: 36
Views: 1509

Re: Gen 3 950 dominator

I did this to show that a PV that is either open or closed at idle has no effect on idle fuel mixture. The carb is one of a pair of external boost referenced PV carbs, internal vacuum supply is plugged. Engine RPM was later brought up to the point boosters were active and confirmed the PV operation,...
by jmarkaudio
Sun Aug 18, 2019 9:10 am
Forum: Engine Tech
Topic: Gen 3 950 dominator
Replies: 36
Views: 1509

Re: Gen 3 950 dominator

At this point I would be afraid of anything Holley tech tells you .... If you are running no PV you want the jets square, and depending on distribution on the track it may even want more in front than back. I've been thru the 950, it doesn't take a lot but needs the adjustments I suggested.
by jmarkaudio
Sat Aug 17, 2019 5:42 pm
Forum: Engine Tech
Topic: Are the "aerodynamic" billet 4150 main bodies better performers?
Replies: 6
Views: 843

Re: Are the "aerodynamic" billet 4150 main bodies better performers?

If you research Venturi then you find that there are ideal entrance and exit tapers to lose the least flow thru the Venturi. If you stray too far then you create turbulence, not good for airflow/reduced pumping losses or booster signal. I've seen issues with the Ultra 950 bodies, and with Demons ove...
by jmarkaudio
Thu Aug 15, 2019 1:04 pm
Forum: Engine Tech
Topic: Gen 3 950 dominator
Replies: 36
Views: 1509

Re: Gen 3 950 dominator

It should have a built in bypass thru the air cleaner stud.
by jmarkaudio
Wed Aug 14, 2019 11:52 pm
Forum: Engine Tech
Topic: Gen 3 950 dominator
Replies: 36
Views: 1509

Re: Gen 3 950 dominator

If it is a single plane intake you should see the same response from both sides of the carb. As far as the secondary idle, just set the primary t-slot exposure and use the secondary to set idle speed. As long as they don't get overexposed, at that point you would add idle bypass air.
by jmarkaudio
Tue Aug 13, 2019 5:44 pm
Forum: Engine Tech
Topic: Gen 3 950 dominator
Replies: 36
Views: 1509

Re: Gen 3 950 dominator

Having the secondary closed more is OK, having correct primary exposure allows the transition circuit to respond correctly to small throttle openings. I've been thru a 950 already, do the things above and it runs fine.
by jmarkaudio
Sat Aug 10, 2019 11:08 pm
Forum: Engine Tech
Topic: Gen 3 950 dominator
Replies: 36
Views: 1509

Re: Gen 3 950 dominator

The Gen 3 Dominator 950 is close, needs a couple tweaks. It has 3 open emulsion bleeds, put the open in 1 and 4, plug the other three, it requires buying blank headed 6-32 bleeds. 28 Main air bleed. And lower the idle feed, this requires buying 6-32 x 1/8 brass set screws and a tap. I suggest a bott...
by jmarkaudio
Fri Aug 02, 2019 10:11 am
Forum: Engine Tech
Topic: Plenum fuel injection for reduced IATs?
Replies: 49
Views: 1957

Re: Plenum fuel injection for reduced IATs?

Or change fuels. VP C-25 has an overall low boiling point, if you can use an oxygenated fuel try Q16. Q16 needs a bit more fuel added...
by jmarkaudio
Fri Aug 02, 2019 10:02 am
Forum: Engine Tech
Topic: Do IFR's Have a Effect at WOT?
Replies: 28
Views: 1614

Re: Do IFR's Have a Effect at WOT?

Reducing the idle feeds alone would bleed less air in at WOT. Try dropping the jet one, see if that helps.