I am new to the site but I thought that this would be a good place to start for some answers to my questions. First off you must know I am not a mechanic and not that familiar with motors as far as detailed info. My question is this: What can be done to get more torque and hp out of my 1973 buick 455? I have already installed a new edelbrock intake and carb. I have this motor on my airboat and I need to generate more low rpm torque and hp. My max rpm is 3,000 due to the propeller limitation. Any ideas would be greatly appreciated.
I don't think I am the guy to ask, but I would look at cams. Either a specially ground one, or an RV type cam and I would experiment with running it 4 or 6 degrees advanced. Maybe even more...
A cam grinder who had done boat cams may be able to give you some good ideas
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your stock quadrajet was the 800cfm model although the buick blocks seem to like a carb a little on the large side.
the stock 73 455 is well down on compression (~8.5? as opposed to 10.0:1)from the stock 1970 engine and you can recover most of that just by getting 1970 spec pistons although the combustion chamber is also a couple of cc larger.
http://www.buickperformance.com/pistons.htm
hypereutectics would be an option but you'd want to have the bores machined for roundness and alignment for sure so you might want to overbore the block while you were at it. .030" is 5 ci.
headers, natch.
head work never hurts but i don't know that you want to concentrate on it given your low rpm.
the Stage 1 spec valves would probably help if you don't have them already. some non-Stage motors came with them from the factory for some reason and all of the buick heads can be fitted for them.
http://www.buickperformance.com/455hdcompare.htm
and now a question for you....
airboats in new mexico???? dude, wth...
The way to crush the bourgeoisie is to grind them between the millstones of taxation and inflation.
Vladimir Lenin
Government schooling is about "the perfect organization of the hive."
H.H. Goddard, Human Efficiency (1920)
i've somewhat reconsidered my original statement about the new carb you've got. with a maximum RPM of 3000 the stock carb was WAY more than you will ever need. if you've got problems with throttle response you may actually want to reduce your carb size, possibly to a large 2 barrel + adapter plate.
according to Holley's web page this is how you calculate your CFM needs:
http://www.holley.com/HiOctn/ProdLin...FMSC/FMSC.html
"Engine size (CID) x maximum RPM / 3456 = CFM
CFM @ 100% volumetric efficiency
most Street engines are capable of achieving only about 80% VE"
using this formula you're looking at:
455 * 3000 / 3456 = 395cfm
considering your engine is still pretty stock your max actual CFM needs are likely to be closer to 316cfm.
i was running a 2 barrel 650cfm Holley (don't bother looking for them, they haven't been made since the 70's, Holley's largest now is the 600cfm 4160) in my 455 equipped race car and it was pulling past 5500 rpm with an adapter plate on a stock 4v intake(the only two barrel intake ever produced for the buick 455 was for certain models/option packages in the 1974 production year). YMMV. dealing with only two throttle plates gives smoother throttle response as well.
[shrug]
however, if you aren't having any problems with throttle response than keep what you've got and don't worry about it.
The way to crush the bourgeoisie is to grind them between the millstones of taxation and inflation.
Vladimir Lenin
Government schooling is about "the perfect organization of the hive."
H.H. Goddard, Human Efficiency (1920)
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