Right now I Have a 350 with a 4 barrel Holley 600 on it. It has HEI and Im thinking about getting the Super HEI kit from Summit. It comes with the MSD Ignition Box and the MSD Coil, and Soft Touch Rev Control, Will I get better Throttle Response with this? Thanks

 

Unless your ign. system right now isnt working right, no. I put a MSD 6A box on my car, along with other new small ign. parts (coil wires plugs) and didnt notice a real difference. those people that say you gain hp by putting a ign. box on, are either full of it, or their previous ign. system was sucking. i guess it is arguably better to have a MSD ign. box, but put ur money else where first.

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• 83 Z28-- not a pretty site to look at, 200k miles and im sure it was treated like a rental car every day of its sad life(before i got it).. sold, thank the lord
• 74 Z28-- 383/400, green on black. pretty clean. FOR SALE!!!

 

What should I put my money into to get better throttle response?

 

More base timing. Increasing that gives better low end grunt. But be careful of pre-ignition.

A better ignition is only good for 2 things. 1.-Higher RPM range
2.-A more complete burn to use all the hp your engine has available.

That's it. It can't make HP, but it can make good use of all the power that's there. So if you had a great engine combo w/ a badly matched ignition, then you would see an improvement by upgrading. But that's it.

[This message has been edited by AJ_92RS (edited July 09, 2001).]

 

I have a 350 engine that came out of a catalog ( so I was told by the other owner) it had 330 hp before headers and all that junk. When I hit the gas there is a big delay then it kicks in. Im still gonna get it for better starting.

 

Sounds like an accelerator pump issue.....



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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R
and 2 POS commuters...

R.I.P. #3
"He can see air"

 

How much is a new accelerator pump?

 

The pumps for holleys are cheap.....you should check for the proper setting of the acc. pump arm first, and make sure all other parts of your tune, timing, etc. are in spec.

The only PITA part of doing the acc. pump on a holley is that you have to remove the front bowl to change it

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R
and 2 POS commuters...

R.I.P. #3
"He can see air"

 

Honestly I don't think its the accel pump, I just think I need some more spark. I have problem starting it when its hott, even with a new battery and starter

 

When you say it has a hard time starting hot, do you mean it cranks for a while and then starts, or does it have a hard time cranking..??..??

2 different problems.....

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R
and 2 POS commuters...

R.I.P. #3
"He can see air"

 

It cranks kinda slow, but it starts everytime but it cranks slow when it is hott. What could cause this?

 

Your timming is advanced way to far. Is it the GM Performance Parts 350HO 330hp 380TQ engine? What year balancer is on the car? These engines dont come with a timing tab and one much be purchased separately to match the balancer. How long is the timing tab on the timing chain cover now? Can you check the timing from the side just above the P/S pump or do you have to look behind the water pump to see it? If a '76 and older balancer style was used as recomended by GM you need the shorter timing tab and you will be able to see the tab just above the P/S, by using the longer one the timing will be set WAY advanced.

 

Get rid of the holley and slap a q jet on there. Instant better throttle response and gas mileage and at worst a tenth slower...but considering you don't have the first clue on tuning the holley it might even be faster for you, and adjusting the secondary metering on a q jet is gravy compared to a holley.

Basically, unless you know what you are doing, holley's are junk. I'd be willing to bet that ALL of your problems are in that carb and it's tuning.

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Ed Maher - Moderator @ The TPI & Carb Boards
92 Z28 Convertible - Quasar blue / Tan top
LB9 4L60 GU2 G80 - stock, soon to be sleeper
-=ICON Motorsports=-

- Definitely prototypes, high powered mutants of some kind. Too weird to live, too cool to die

 

Im not the one who tuned my carb, a guy that works for federal Mogal dragsters in the NHRA did it for me.

 

Well, assuming no other problems, a bog when you hit the gas is a sure sign of a carb tuning problem so i'd say the guy didn't do a good job on your mild 350s tuning. Either your accelerator pump is bad or the shot is wrong (too little/too much volume, too short/too long duration) or something is wrong with your metering transition itself, like too stiff/weak of a PV, incorrect jetting that works OK under load but fails you in transition. Or you could even have some funk in your air bleeds. If we're taolking about a bog when you nail it, there's a whole 'nother set of problems to look at, etc, etc.

Holleys are finicky carbs that make great WOT power. Tuning them for a mild street application is very tough b/c they suck under every other condition except WOT. My advise, swap carbs or start reading books on holleys. You have some tuning to do.

 

The only thing an ignition system will help is starting and if you're running rich it will help to burn more gas. It will also make the engine idle and run smoother until the plugs go after about 200 miles(or less). Then you're back to square 1. It really starts to work good on engines that are blown or have high compression.

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'87 Bird 350 .060 over 700R4 + Lots more