horsepower??????????????????

[bchbm]

I just bought a 85' chevy c10 custom deluxe from my neighbor. It has (so i have been told) a 455 stage 1 from a 73' Riv. I need to know the stock, manufactured, horsepower specs. I have heard that the factory specs are a little below actual but would like to know what the actual is. I am new to the buick world and am in the process of getting the truck legal for on road usage. Basically i want to smoke this danged mustang that passes me daily and i need to know if it can. ANYWAYS!!!! The engine is (so i have told) bored of .040, cam, very high ( i think) compression. I was told that one of the cylinders was pressing around 180 on a compression test and that the engine runs perfect on regular pump gas. My neighbor built it and i want to know if he is true or not. I am looking into a dyno test but dont know where to go. Anyone know where i can dyno in Virginia Beach, Virginia? Oh, he told me the thing has 500 horse. Dont know if that is true or not, hopefully it is or all of that $3,000 bought me a really heavy gas guzzlah. LOL!!!

[Dr. Frankenbuick]

The stock 73 Stage-One Riv was rated at 270 HP and 390 Tq, and had 8.5 to 1 compression. The way HP was rated changed in 72, and the compression was down from a high of 10 to 1 in 1970. The actual flyheel numbers for the 73 Stage-One are close to those listed for the 71 Stage-One engine that also had 8.5 to 1 compression. The 71 is listed at 345 hp and 460 Tq.

It is not too difficult to put one of these engines releiably over the 500 HP mark with the right combination of parts and machining. Ask specificly what parts he used and what machining he had done, list them here and we can take an educated guess at your HP. With that kind of power, you should be able to bag most Mustangs, but not the one in my signature.

[bchbm]

ok DOC, here is what i have so far. The engine came out of a 73' riv' GS. Tunnel port heads. It is running 10-1 pistons. Has as "off-shore" cam. For boats. Dont know specs. He said it has the tunnel port heads. Its overbored by i think .40. Let me know some questions i should ask him. Also how i can find out the answers without doing a complete breakdown of the engine. OH, does the th-400 have a manual or electric kickdown???????

[Dr. Frankenbuick]

10 to one pistons is a good start. It would be nice to know the make of the ones he used. It would also be nice to know if he had used any aftermarket fasteners for the rods, mains or heads. I would want to know if the block had been decked, if the heads were milled, and if the rotating assembly had been balanced. What intake was used: stock cast iron or aftermarket aluminum? What type of carburetor is on the manifold, and what type of exhaust (headers or manifolds) is used?

The things above tell us the general power level the engine was built for, but the determining power factor is the heads. Stage-One and regular heads used the same castings, but the Stage-One heads had larger valves. You could not tell the difference externally. I have not heard of tunnel port heads in the 25 years spent in, around and under Buicks. I would want to know if the heads were ported, and if it was by someone that knows Buick heads. The difference between a stock head and a ported Stage-One head could account for well over 100 hp. There is no way to get 500 hp from a 455 using pump gas without some porting to the heads.

With all that said, an old Buick guy I know told me that the less people seem to know about the engine or car they are trying to sell you, the more they may not want you to know. See what else you can uncover, and let us know what you find.
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[bchbm]

ok doc, i need a break from the research of my engine. Can you tell me what is the stage 1 engine capable of producing (hp's and torque) safely. By safely i dont mean legal or wheelhopping aweswome safe, i mean without blowing up the motor or spending millions. Truthfully, i would like to know what i would need to do to make the stage 1 reach 03' cobra convertible smoking capabilities. Now dont get offended Doc, when i reach the time of my life when i can afford a cobra..............i will!!!!! I have been a ford guy my whole life and i am only 23. Now i own a chevy with a buick motor. Guess you could call it "85 c-10 chevroluick. LOL!!!! or a Buickolet". Talk about Custom Deluxe, LOL!!!!! Anyways. OH, what are the weak points of the lower end of the motor. "what the hell do you mean", you ask........well i have been looking into dropping a high performance 302 in my 89 Ford Ranger and making it a rock chewing, mudbogging machine. But one of the weekpoints is the connecting rod to crank bolts. To small!!! I have always wanted a big block but couldnt afford it. Now i cant afford a 6 cyl but have a big block. ANYWAYS. Thanks for the help doc. You are the man i reckon i am going to get most of my help from so i will do what i can not to discourage you. Thanks again.

[bchbm]

Thanks for the advice doc. Well the neighbor wasnt home today. Thats the guy i bought it from by the way. Anyways, i did a bunch of research on the net today and decided to go out and stare at the engine for awhile.

Intake Manifold looks like iron. It has the firing order, the cylinders are numbered and had another number close to carb...B-1243020-1. I reckon it is stock.

Carb is a Rochester Quadrajet. Dont remember the numbers but after finding the numbers i researched the net and found the carb to be a 455 800 cfm not a stage 1 455 800 cfm. The guy i bought it from said it was an Edelbrock. Guess he lied.

Also i found on the drivers side cylinder head towards the front (radiator side) next to what looks like stock exhaust manifolds the letter number sequence of A 75.

That is what i have so far. Any questions let me know. Thanks again and tell the old Buick guy that he is right. I have uncovered some things so far that really **** me off. I mean, I spent $3000 on a truck that supposedly had 500 horse. The only thing he said he did was get it running, edelbrock carb, new oil and water pumps, "TUNNEL PORT" heads. Now i find that it is a stock carb, no such thing as tunnel port heads, and most likely is not running 500 horse. Allwell, guess i am going to have to it then right. Make it a badass chevroluick, wheelhopping cobra eater. LOL

[Dr. Frankenbuick]

OK, one thing I can say for sure is if you have as much energy for your truck as you do for posting here you will have 500 ponies in no time.

The Stage-One can be built to 550 hp before a block girdle and other expensive parts are needed. This is providing you have used good rod bolts. Main studs would not be a bad idea either. The main webs are the weak point in this engine. If you build much over 550 hp and the mains can pull out. There are those that get away with 600+ hp with lightweight, well balanced rotating assemblies, but it is a calculated risk.

As you move from 500 to 600 hp the engine is less and less streetable. The compression needed makes the octane requirements higher, the transmission converter stall rpm will need to be upward of 4000 rpm and the vacuum will no longer support power brakes. I would say that somewhere between 500 and 550 hp you no longer have daily driver.

A solid 500 hp build needs 10 to 1 or better compression, a performance camshaft, heads ported by a Buick specialist, a good intake (stock can be made to flow OK for this), headers or ported exhaust manifolds flowing into a 2.5” dual exhaust system and a good HEI or better ignition system. Your Q-jet will work fine on this engine if it is rebuilt for it.

You will also need more stall in the transmission torque converter then stock. The performance cam will move the power range higher, and your converter will need to reach that range quickly. I think something close to a 3000 rpm stall converter will work. Your rear gear will also need to be 3.08 and preferably numerically higher in order to feel the benefit of the combination in the seat of your pants.

There were big port heads in 67 and 68? that had slightly larger intake ports, but they did not have Stage-One valves. They needed to be converted to Stage-One valves and did not provide a lot more hp then Stage-One head once converted. Head porting and matching the rest of the combination is the key to power in this engine.

Finally, a truck is just plain heavier then the nimble little pony in my stable. It takes less hp to power a lighter vehicle to the same speed as a heavier vehicle with more hp. Your local PIA Stang has you at a weight disadvantage. You will need the 500 hp and to put your truck on a diet to spank him properly. Then we can see about bigger fish up north.