Inliners International Forums General Discussion Engines Preparing a Chevy 250 for NHRA Stock Class

I am thinking of building a full size 66 Chevy (Biscayne or Bel-Air) for drag racing in NHRA V/Stock class (22lbs./hp, 4 and 6 cyl. only). I would like to hear any suggestions this group might have. The rules allow headers, any battery operated distributor, up to .075 over the stock bore, stock intake and carburetor. The engine must meet the specifications listed by NHRA.
Back in 1972 I prepared a 65 Bel-Air 4 door sedan with a 230 for O/Stock (24lbs./hp). Back then the rules only allowed .035 over stock bore and you had to use the stock exhaust manifold but you could have open pipes. I had a best e.t. of 17.6 seconds on a 17.4 record with a 4.11 rear. The current index for V/Stock is 15.55 seconds. Is this attainable?

are you allowed to cam it up? can you modify the intake/carb, head, raise the compression? tom

I have much experience with engine building and prepartion experience with many of those Comp,Super Stock and Stock classes!The first thing you need to do is take full advantage of all the allowances that are permitted for overbore, stroke+/- the .012 that is offered and rod length +/- dimensions. I could write a book on the next courses of action to get you going,so I'll just offer to have you PM me with your needs as you come to them! Is "filling" the block allowed, if so you will need to follow some "secrets" I've found that will be a huge benefit. Just Let me know....

The rules allow any cam as long as it doesn't have any more lift than the stock cam. I don't believe they check the duration. You can 'blueprint' the engine, bringing everything down to the minimum (deck clearance, etc.). They do cc the heads. It has to be a stock carb or approved replacement bolted down solidly - no air leaks. No porting or even sandblasting of the head or intake allowed. Any rear from the same manufacturer so I can put a 12 bolt in it. Any transmission as long as it has the same number of gears as original so I have to run a 3 speed.

The rules don't say anything about filling the block. I'm not quite sure what that is. You are allowed to use an electric fan and water pump. You can even use an electric fuel pump, but you have to have a belt-driven alternator.
The first thing I need to do is find a car and a couple of spare motors. I have a 63 Chevy II Nova 4-door that would fit the same class, but I would have to use the 194, and mine has a Powerglide. I suppose I could put a stick in it, but I'd rather find a 66 Biscayne or Bel-Air. My first choice would be a two-door sedan, but a four door would work.

Many companies like Comp Cams, Crane and Cam Motion can provide you with a "cheater" cam like will be legal for your needs.

Would you get any break in running a heavy Biscayne?

If you run the Nova,would you have to add weight?

I would go w/the lighter car if possible.

MBHD

The lighter car has to use a smaller engine. Chevy II = 120hp x 22 equals 2640 lbs, plus 170 for the driver for 2810 minimum weight. Biscayne = 155hp x 22 equals 3410 lbs, plus 170 for the driver for 3580 minimum weight. You can run at the minimum weight regardless of the shipping weight of the car. You can go up or down one class also and run at that minimum weight.I'm actually planning on going from U Stock -20 lbs/hp to V Stock - 22 lbs/hp. Besides, I already have a set of Vipar headers for a 65-72 full size Chevy.

with the 22hp/lb rule. lets see 120 hp =2640
150 hp =3300
170hp =3740
with that said, do they mean factory rated hp? if so then run the chevyII with the PG and put a big stall in it with a big duration cam and low rear gears. also put a switch on the alternator to kill it during the run. it will eat 5 hp.

All the classes are evaluated by weight per HP, based on the factory HP of the engine for a particular car. The higher the classes up the alphabet ie...D,C,B,A, the farther under the indexes are and harder to compete. Not that any of them are easy....

That cut-off switch is a good idea! Good suggestion....

The rules say the alternator must be functioning. I think that rules out the switch. Any suggestions for headers for the Chevy II? The Clifford headers seem to be universal, one size fits all.

You can also use a 230. They came in the ChevyII's 62-64 194. 65
was the first yr for the 230.67 was the first yr for the 250's
So unless your stuck with YR & cubes.

Many cars today can run a full second under their indexes, and more. This is important as any race against a similarly classed car (e.g. class run offs) the index does not apply - you can run as fast as possible. Plus you need a performance cushion for bad track conditions, bad air, etc. I would plan to run in the 14s to be competitive.
Are modern engines allowed in the class? like V-6s and OHC / DOHC - 4 valvers? You could be at a disadvantage as rules would allow these engines to produce potentially higher output with similar engine mods, plus they will be in later, more aerodynamic bodies.
Lots of "rules bending" goes on in those classes. My friends national-record-holding compact Stocker had body mods so bogus you could easily lift the front wheels off the ground by lifting the front bumper when the engine was out of the car. 150 lbs of lead were hidden in the rear bumper, among other costly-to-hide mods.

You guys almost have me convinced to build up my 63 Chevy II. Anyone have a rebuildable 194, maybe even with a 3 speed? I have a 235 out of a 59 Cameo truck to trade - see my classified ad.

Have you decided which engine/car combo to build!

I'm still trying to decide IF I'm going to build a car and go racing. Right now I'm working on putting together a budget. The Chevy II would be the cheaper option at this point since I already have it. The Biscayne/250 fits the class better. But the 230 is really my favorite so I've looked at Chevelles that fall close to the weight break. For any of them the cost of building a competetive motor will be the biggest factor. Next will be getting a rear end setup that works and lasts. It seems to be a lot easier to find a 12 bolt for a Chevelle than a Biscayne/Bel Air. I don't know how well the Chevy II rear would work.
My wife still isn't thrilled about me racing. She even accused me of trying to re-live my youth - imagine that!

Well, after all the trouble deciding between the Chevy II and the Biscayne I ended up buying a Chevelle. I am getting a 66 Chevelle 300 4 door with a 230 and 3 speed. I will have to ballast it a little to run in V/Stock. At the factory shipping weight of 2934 lbs. it works out to 20.96 lbs/hp so would naturally fall in U/Stock. I will have to weigh 3080 to run in V. An extra 230 and 3 speed come with it. So I will rebuild an engine locally to get on the track then take my time building the Super Trick motor.

Make sure you keep pics coming of the progress of the engine and car as you build it up!