CamaroLuvnPunk

Hey,
I am in the process of buying this Holley 750CFM carb from a guy. Now its at the post office and all I have to do is pick it up.
Now I want to kept it on until I rip all the emissions and other computer stuff off the car and put a bigger cam and better intake on.
However will I notice a difference with the 750 on the stock everything?!?! Or will I just be lossing power until I put a new cam on. BTW the 750 is a manual choke.
Also what would be a good cam combo for a Holley 750 with a Holley dual plane intake?
Car Craft did this Erson cam thing with a 600 CFM Holley and a dual Holley dual plane intake on a 350 and it gained 77 horses... lost a few foot pounds..... but nothing a good true dual system couldn't fix right?
Erik

SUPER-SPORT-CHEVY

The holley on the stock intake wount fit.
You could use an adaptor plate but then you will run into clearance issues. A pro flow air cleaner might squeze under there but it might not it just depends on the model holley. If you put the 750 on the 305 it will need some tunning but you will notice a increse in power/drop in fuel economy unless it its really tuned well.
The wieand stealth is a good manifold better than edelbrock in most areas and any 114@.50 duration cam should fall into the power package that is advertised for a hp gain.
SSC

Biochem

Get ready for a hell of a lot of fuel line modifications too! A 750 is a huge carb for a 305... especially a stock 305. Be prepared to have it be a dog until you get the mods. Pick your cam carefully and I would suggest a higher stall converter too.

A Stealth manifold would be a great addidtion to your engine at this time. I hope you don't need to pass emissiona though...

Is it a vacuum carb or a mechanical secondary carb? Do you have a manual or automatic tranny? These are important factors in choosing the proper carb...

------------------
1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

[This message has been edited by Biochem (edited June 02, 2001).]

bottledpower

a 750 on a stock 305 is a major overkill. get ready for a tuning nightmare. not to say it isnt possible, just isnt necessary.

82camaro

Unless you plan on turning alot of rpm, a 750 is way bigger than you need. A 600 will put a 305 to 6000 rpm without much trouble at all.


------------------
350 with stealth intake, holley carb, 470 lift cam. 700r4 with .5 boost valve, vette servo, tci lock-up kit, B&M megashifter. Richmond 3.73 gears, powertrax locker, timkim bearings, synthetic lube. Custom 3 inch single into 2 2.5 pipes. 1 1/2 drop springs, 1 5/16 solid front sway bar, 1 inch rear bar, custom subframe connectors, custom LCA relocation brackets. Kobel ground FX, current red metallic paint. Lots of other stuff...
82camaro

87SC/SS

I agree with bottledpower and 82camaro. That holley is way too big. Example: I have an 87 camaro with a 350, Comp Cams XE268, and ported and polished stock heads. I put a weiand high rise single plan and a holley 750 on it just to see what would happen. It ran way to lean until about 3000 rpm and had no throttle response. It ran so lean in fact that the header pipe on cylinders 5 and 2 were glowing red because of the heat. After a little tuning I got the mixture right but it still runs too lean. If thats the situation on a well modded 350 imagine what it would do on a motor with 45ci less and a stock intake. I'm sticking with a Edelbrock performer and a modded q-jet. Just my 2 cents, but from personal experience as of yesterday .

Huckster's '84 TA

Your car will run like crap also if your ignition is comp. controlled.

84TransAm

750 is overkill, don't just assume it will work out. Unless it's a real hot setup (being a 305 i highly doubt it) i would use at most a 650, with 600 being ideal.

As for modifications to be made, All you need is some Rubber Fuel line with an inline filter in the line. You need an adaptor, as the spreadbore and squarebore won't fit directly without it. Also you will need a vacuum controlled Distributor, or you can kiss performance, and mileage goodbye (which is what you're doing with a 750 anyway)

------------------
--Steve S--
1984 Trans Am 305 LG4, 5 speed Daily Driver, Flowmaster 80 Series
Holley 600 cfm & vacuum advance
Soon: Edlebrock Intake & TES

BadSS

Ok,, I can’t stand it. A 750 vacuum will have no problem even on a stock LG4 305 with proper tuning and a few “extra parts”. Must haves in my opinion (not just for 305s) is the secondary quick-change spring kit (with springs) and a metering block to replace the metering plate (for easy “jetting”). – this gives you a very similar set up to the new Avenger series carbs. Squirter size and pump cam may have to be changed / adjusted, but usually a jetting change and heavier spring,,, that limit the flow rating and rate of opening,, are enough for the 750 to work on a 305,,, and work well. If you’re going to run the 750 Holley don’t expect it to run right just bolting it on. If you’re not familiar with tuning the Holley carb,, get a tuning book. The smooth transition Quad to Holley adapters work just fine on a stock intake also (I don’t know about hood clearance on the 3rd gens). If you want to run the Holley, you’re not going to be able to use your computerized ignition – which means you’ll need to swap to at least a vacuum advanced HEI.

HOWEVER,,, the computer quad can be tricked out to perform near,, if not just as good as the Holley in most street cammed applications - especially on a 305. From experience,, I only dropped a little over .10 seconds on a 13.18 car after spending over $400 on a new Holley 750 vacuum carb, parts needed in tricking it out, and Accel distributor. The car was noticeably slower after the initial swap,, and took a lot of tuning on the carb and the ignition curve just to get it back to where it was before the swap. So,,,, will the 750 Holley work on a stock 305? Yes - no problem if you’re able too properly tune it. Will it be worth your time, money, and effort to swap? Not in my opinion. You’ll see very little if any et gain over a tricked out and tuned Q-jet,, and have more of an opportunity to slow the car down and have driveability / tuning “nightmares” as someone called it with the Holley and vacuum advanced distributor.

A good intake for the 305 with the computer is the Edelbrock 3701, if you’re planning on bumping up in cubes later on,, the Wieand 7525 single plane works well and kills very little low end. The largest cam I’d run on the computer for a 305 is a somewhere around 210/220 on a 110 spread – but will also work well on a 350. My favorite 305 cam is a 205/215 Lunati on a 112 spread, my favorite 350 cam with the computer is the 218/224 X-treme. You can run bigger cams than these I’ve mentioned with the Computer Carb system,, but tuning gets a little tricky. Get the Dough Roe(?) “How to Tune Rochester Carbs” book and knock yourself out. I think you’ll be amazed at the difference tricking on the Quad will make,, even a stock LG4. It was not uncommon for me back when these cars were relatively new to put a high 16 second LG4 in the mid to high 15 second range tricking the Q-jet and playing with the initial timing.

Big454blockchevy

You can run a badly tuned 600 cfm Holley carb on your engine and then run a tuned 750 Holley carb and the 750 would give you better performance and gas mileage than a 600. My point being that a 750 correctly tuned will be good on your 305.

------------------
Big 454 72 Chevy Nova
383 86 Camaro Z28
10.5:1compression Dart Pro 1 Aluminum heads 215cc,234dur.488lift exh&int,Victor Jr. intake, 770 Holley Avenger vac.sec 400 crank,flat top pistons,tranny shift kit,2500 stall converter. 3.42 ,Hooker Headers,2.5inchpipes with 40 s. Flowmasters,MSD coil,MSD module.