Inliners International Forums General Discussion Hi Performance Clifford engine kit

I was looking at the Clifford site and they have a 250 hot rod engine kit. Anyone use one of these? Also, who can I send my head to for work, when I have the money. I live in the Chicagoland area and do not trust any of the local shops for this. I have a good head, just needs the work.

Dear Dick;

Larry/NOVAMAN will know.

Good luck, John M.....

I am looking for a realistic power combo to do and later on do the big head work. With a port and polish job, bigger valves, and good springs. I also want a good street cam, 500 Edelbrock, flat top pistons, a decked block and balance and blueprint, headers and a 5-speed and 3.55 posi. What power am I looking at?

Taken from another posting, but good answer. Well if you read all the ads for performance parts and add up all the claims you can easily come up with 300+ horsepower. They do it all the time in the magazines, right?
But the reality for a stock 250 in good condition internally goes more like this..... original 155hp, a better intake and the right carb or carbs along with a better exhaust system, good street cam, and a decent and accurate ignition system should bring it to about 200hp at the flywheel. That's about the end of the story for parts that just sort of bolt on.
The big horsepower maker is in the cylinder head and compression ratio. This requires going inside the engine and doing what it takes to build compression and get the head flowing well. The big money gets spent on the head but the end result should bring you to a very realistic 250 - 270 hp at the flywheel on a street driven 250 with pump gas and no steroids ( Nox ).

The key to all of this is to plan it all from the start and select both parts and machine work that all works together. Bolting on a drag only intake manifold and carb to an otherwise stock engine and exhaust won't do much in terms of added horsepower or driveability.

Mike G

Wow!!! Somebody actually read one of my posts!


Mike G

Mike G, I read your post and apreciate it. I guess one of the problems I am having with the L-6 is there seems to be no real instructions. I have done SBC and Pontiac motors and they give you the combo of parts and machining you need to do to get whatever HP you are looking for. I have not found that here, not that it is bad, just harder to figure out what you want to do.

Thanks for the comment Dick. You bring up an interesting point as to no specific combinations for one to refer to. Might be something all of us as a club could work on based on what works for us?

Meanwhile the best published source for making a decision on parts is still Leo Santucci's book on the 194 - 292 Chevy inlines. There are some very good recommendations from experienced engine builders regarding cam, carb, etc, selection for an intended purpose. You won't find a blueprint master list of every part to go shopping for to end up with xxx horsepower but if you read carefully and fully apply what is in that book you can't go too far wrong.

Mike G

PS: The most (if lucky)you can get out of ANY engine is .8 HP per CID @ sea level.

Now if you add a blower or NOS the game changes.

I'm sure you have some basis on only getting .8HP per cubic inch but it made me wonder.....

In 1957 Chevy amazed the auto world by producing a 283 HP 283 cube engine in the Corvette and passenger cars. By 1961 that same 283 was giving 315 HP. Their 327 cube job was giving as much as 350 HP with a carb and 375 HP with fuel injection.

Ford had the hi-po 289 cube engine that did 271 HP and although not quite what Chevy was getting it is still a respectable .93 HP per cubic inch.
Ford's 406 engine was offered in a 406 HP version.

Mopar had 413/413, 425/426 hemi, 375/383, and so it goes.

These are all engines of the 60's vintage and didn't have the electronics and black boxes of today's engines. Todays smaller engines with all their electronic and other features are close to or over 1 HP per cubic inch. My wife's Sebring with a 2.5L ( 152.5 CI ) V6 has a net rating of 155 HP as measured by todays horsepower rating methods.

If you are talking about just adding bolt on parts to an otherwise unmachined 250 inch Chevy inline then I agree 100% - you'll do well in pulling 200hp from it. As mentioned before though with proper attention to head flow and compression it can easily exceed 1 HP per cubic inch and still be naturally aspirated and on pump gas only. Thats how the factories did it back in the 60's.

Still the cheapest way to get horsepower is to just buy an air cleaner decal that says 450 Horse Power Turbo Jet and put it on the 194 in your Nova.

Mike G

Dear Mike;

The .8 is an adverage used over the years with 1.0 as a 'goal' of sorts.

Most of the "factory ratings" were just for sales purposes except for perhaps the fuel injection ones on the Corvette.

I should have included EFI along with blowers & NOS.

JM.......