compatible carburators for 1986 454 engine?

Question

i prefer holly carbs

Answer 1

depend,s on the manifold................Holly does make a spread bore replacement carb.........go for at least a 750 c.f.m.

Answer 2

Country Boy answer one of the best I have seen and yes, the Quadrajet is a good carb for the reasons explained above, but harder to work on and tune.
If you are determined for a Holley, the above answers are good and real, but us OLD TIMERs know that Holley USED to produce the spread bore in 800 CFM. Perhaps you can find one of those.
I would also consider to lighten the advance springs in the distributor and turn initial timing up SLOWLY 0ne or two degrees at a time.
Good Luck,
PS Don't ask my when or how I know about the 800 Holley Spread Bore carb..but when was the last time you saw a 454 in a car?

Answer 3

I own a shop, a drag car & truck, and have messed with racing parts for years. I'll agree with you on the holly carbs as being good carbs. It just depends on what you are going to do, and what your budget is. Barry Grant makes some outstanding carburetors, but they also have a not so outstanding price tag attached to them. It depends a lot on the intake you are using, as a holly is a square bore carburetor, and if your intake is for a spread bore such as the Quadra-jet, you will have to adapt, and might get into a height problem under the hood. I think I would see if I couldn't use a 750-800, dual line, double pumper Holly on it. They are easy to work on, easy to get parts for, and all around just a better carburetor, but thats my opinion, and you know what they say about opinions? Edlebrock makes an adapeter that is 1" tall for the Holly, and if you have the room, do it!
Glad to add my 2 cents worth!!!

Answer 4

For gosh sakes PLEASE never put a double pumper on a street car. You'll get terrible mileage and a stumble when you step on the gas to the floor especially with an automatic transmission with a high end gear ratio. If you have or can find a high rise aluminum intake with 180 degree divided passages like the 69 375 hp. 396 or the 425 hp. 427 intake grab one. The throttle response is outstanding.

If you find any square bore intake manifold with a center divider (all holes the same size or two divided slots with semi-circles at the ends) you can use the following: New Chevrolet Part 319170097 Holley duel feed, center hung, vacuum secondary 650 for great off idle response.
If you'd rather have a 670 Holley Chevrolet part # 19170092 with vacuum secondaries, center hung floats and dual feed float bowls.
Chevrolet #112485506 is a 750 cfm with vacuum secondaries, dual center hung float bowl. carb.
Chevrolet #19170093 is a 770 cfm Holley with vacuum secondaries, dual center hung float bowl carb.

Now get this: Chevrolet #12366996 is a Holley vacuum secondary 850, dual center hung float bowl carb.
Not satisfied! Chevrolet # 19170094 is a Holley 870 Vacuum secondary with dual center hung float bowls.

As for Barry Grant Carbuerators, a friend of mine had Ross Racing engines in Ohio build a Chevy 350 .030 over Dart block and Dart platinum heads with 49 cc cumbustion chambers. The carb was an 850 double pumper Barry Grant carb. It smoked 3 JE pistons on two ocassions due to burn through. Both times engine builder did not alter the carbuerator.

Another Engine builder said Barry Grant Carbs make amazing power on the top end but from off idle through the transfer stage the horse power drops off and goes lean from 3,000 - 5,000 rpm. From 5,500 - 7,500 it comes back on like gang-busters.

You have a relatively low compression motor designed for torque. The origional Rochester Quadrajet has a cfm rating of 750. It would be pound wise to not exceed 750 cfm's. Believe it or not the origional carb rebuilt by a professional would buy you better fuel economy because of the relatively small primaries with two booster rings hanging in the venturies. It also has two vacuum actuated primaty jet rods that pull out of removeable primary jets as vacuum builds in the intake along with this circuit there's a vacuum power valve that releases added fuel through the booster rings while the vacuum is low in the intake. There's a large accelerator pump that can be shortened overall on the aluminum end to increase the pump stroke inside the pump cylinder chamber.

It has huge secondary mechanical butterflys on the bottom. The top has vacuum actuated butterflys on the top. As vacuum builds in the intake the secondary slowely opens mechanically pulling two metering rods out of the fixed secondary main jets enrichening the fuel mixture.

I know people say these carbs are junk, I think they are not willing to put in the time and see how they work.

If you don't want to spend money on an intake the spread bore Holley is the one for you. The 4105 is a direct bolt on.
Other Holly spread bores are 0-9885, 0-6210, 0- 80555C.
All of these carbs.are 650 cfm, smaller than your origional but would give you better fuel economy than the square bore type. Not as good as the origional Rochester.

Here's a couple of definate upgrade Chevrolet intake. # 19131359 is a high rise rectangular port aluminum dual plane manifold that can be used with high performance cast iron or aluminum oval port heads - same as 454 and 502 engine assemblies.

Word of caution: If yours is a truck engine it has what is known as " peanut heads", be careful when selecting aftermarket intake manifolds. Willy's Carburetors makes high dollar products that are miles ahead of other tuners products.