Hi,

I am looking to build an inline race motor for short circle track racing, so I need strong torque in the 2300-5300 range with it peaking about 3800 rpm. My choices are 4.2, 292 and 300 ford.

I would like to run the 4.2 but I am concerned with lower range torque as compared to the 292 and 300. A four valve head's drawback in the past has been weaker lower range torque. I would be willing to keep the varible cam timing function, but would that be enough?

Any familiar with this kind of build?

Thanks Steve

lower range torque? You do know the motor is a 255ish inch with a four plus inch stroke. It may not PEAK at lower speeds but I bet its torque at 1600 And up pales 250's torque numbers, and probably embarrasses the others, stock it has a very flat torque curve, contrary to most stock sixes.

Dont say 300 inch (FFF-aw you know what I mean) so loud- it may wake up that Frenchie guy!

In stock trim, the 292 makes 300 ft.lbs of torque beginning at 2000 RPM, neither of the other 2 engines you are choosing from can do that. Also, in recent dyno testing with the 292, it consistantly made between 300 to 330 ft.lbs of torque in over 120 dyno pulls with many different cylinder head, camshaft and intake/carb combos. I think the only choice of these 3 engines is the 292 for your project.

stock chevrolet 292 specs are about 280 ft/lbs at 1600 rpm and 165 hp at 3800 rpm. The 2006 4200 has 277ft/lbs at 4800 (advertised to be 95% everywhere else in the rpm range) and 291 hp at 6000 rpm.

Now this is comparing a more race horse (yet stock)4200 with 10:1, F.I.,DOHC, and computer tuning, to a clydesdale 8:1,single bbl carb, OHV , schoolbus/dumptruck plow horse.

I hope the 292 can do as you say as I have a project with an excombine refugee 292. My copies of Tom's dyno-ing seems to make the real star to be the 250, with the 292 never making 300 hp. My take was the 292 never had a strong enough cam to take care of the extra displacement. I would bet if someone built a track 4200 (Self perhaps), that it would so embarass the elder 292 that they would force the 4200 into another class. And I am a fan of the old horse (but I bought too soon).

Now I have never heard of the 300 inch blue oval motors on the track (kinda selectively deaf). Maybe they are allergic to dust.

Frenchie?

SW9 what are the engine rules for the class you want to run? that may help decide which one to pick.I know of a few 300s' that are being used in vintage modified racing and can hold their own with the others.

The rules are open on the motors with the exception of no turbo's or blowers.

I will be running with/against 350 chevy's on an opened wheel car weighing about 1600 lbs.

It would be nice to make it work with 4.2. I might be able to offset the lower torque with some advantages the 4.2 has in other areas:

1. The ability to run higher compression. some say 16 to 1

2. The weight savings 100lbs?. better acceleration, braking and handling

3. Upper midrange and high end power (I just found out my upper range will be closer to 6300 not 5300)

Does anybody know how far over the 4.2 can be bored? I would like to squeeze at least 280 cubic inches out of it.

Steve

I think you just answered your own question right there.

Use the 4.2. Forget about those other dinosaurs. They haven't a prayer of keeping up, given a similar bankroll.

Or the Beemer six

Are you allowed fuel injection?

[quote=sw9]The rules are open on the motors with the exception of no turbo's or blowers.

I will be running with/against 350 chevy's on an opened wheel car weighing about 1600 lbs.

It would be nice to make it work with 4.2. I might be able to offset the lower torque with some advantages the 4.2 has in other areas:

1. The ability to run higher compression. some say 16 to 1

2. The weight savings 100lbs?. better acceleration, braking and handling

3. Upper midrange and high end power (I just found out my upper range will be closer to 6300 not 5300)

Does anybody know how far over the 4.2 can be bored? I would like to squeeze at least 280 cubic inches out of it.

Steve

Not easily. You will run into head gasket issues. The only aftermarket gasket is cooper and no one has yet had any luck to get them from seeping fluids. The stock gasket is nearly bullet proof but you cannot go over bore.

You will get more power by porting the head, camshafts/springs, headers and careful tuning than trying to make the engine bigger.
Put in good rods/pistons, studs top and bottom. Dry sump if your allowed.
Remember that being OHC the valve train weight is very low - don't be afraid to turn the engine hard 7000+ is easy and gear accordingly. The drag race guys turn these 9500+, on the salt 7500+ for 5 miles wot.

Marc,
Do you have any Dyno curves you can post for the N/A 4.2 with or without a aftermarket cam?

Yes, at this point I will be keeping the WT, so it will be EFI.

Steve

Tom,

Only of my turbo engine without the turbo installed. Lower compression, head work + cams... not sure if this helps.