Hey guys I am very new to the gen3/4 small block scene. i run a dirt late model and want to try an experimental engine. I would like to try a 5.3-6.0 in mycar. I have never seen one and have some questions. I will layout some specs / rules and go from there.

1. cast iron block and heads

2. manual / belt driven fuel pump

3 cubes limited to 362 max (I might fudge a little LOL)

4. Headers?

5. 450+ hp

 

The only Gen 3 that had cast iron heads are the 99 6.0 liter truck engines. All other Gen3/4's have aluminum heads.

 

Compared to SBC engines, you can build a competitive LS version for a fraction of the price.

Iron heads are the biggest problem I see here. Early truck 5.3s had iron heads, I believe, but I'm not sure how available (cheap) they are. Is porting allowed?

362 cubes is also a problem if you really want to stay legal and use a 6.0L block. 450+ fwhp is not a chore if you don't have a really small carb rule.

What are all the rules? This could be fun!

Jon

 

here are the rules I am willing to fudge a little on the cu in. I dont think the tech inspector can tell the difference in a 5.3 or 6.0 or possibly a stroker of some sort.

ENGINE:
A. 362 cubic inch maximum, including over bore.
B. Any steel crankshaft.
C. Stock stroke.
D. Any steel connecting rods.
E. Stock type pistons, 2 or 4 eyebrow, may be forged.
F. Dry sumps allowed.

ENGINE SETBACK:
A. Full tubular frames – six(6) inches with ½” tolerance.

HEADS:
A. Steel heads. Must be based on OEM design (Chevy, World, Dart, and Pro are OK).
B. 23 degree heads are OK. NO 14 degree heads allowed!
C. Intake and exhaust bolt pattern must match original OEM head.
D. Valve angle and valve spacing must meet OEM specs for the head being used.
E. Steel valves only. Undercut stems permitted. NO titanium valves.
F. Valve stem diameter 11/32 inch minimum for all engines.
G. Maximum valve size: Intake – 2.055 ; Exhaust – 1.625.
H. NO porting or polishing.
I. Three(3) angle racing valve job permitted. Machine cuts only.
J. Any valve springs, retainers, roller rocker arms, and stud girdles allowed.

WEIGHT:
**Steel angle plug heads - 2350 pounds
**Cars with 604 GM Crate Motor - 2300 pounds –

* Cars with 602 GM Crate Motor - 2250 pounds

***It is the driver’s responsibility to have declared weight displayed on left side of roof. ANY car with weight not displayed is subject to disqualification.

CAMSHAFT:
A. Flat tappet only. NO roller cams.

DISTRIBUTOR:
A. Stock type or magneto allowed.

CARBURETOR:
A. 750 CFM maximum.
B. Any intake manifold.
C. Gasoline only.

 

only issues i see is the 23 degree head rule . Stock the ls heads are 15 And roller cams

If you can get passed these issues make sure your at the ci limit cause you will be making some sick power compared to rest of the pack so you will be getting checked out hard

 

What track do you run at?

 

I think as long as I stay all cast iron nobody will be the wiser as to the internals . no one has a new ls engine, that is exactly why I want one. GM has a new crate engine that is based on the ls family it is a ct525 . I just want to be ahead of the curve and learn how to build these engines for stock car racing. Might like to turn it into a small business if it works well. I had thoughts of trying to use a 5.3 block with 6.0 heads and maybe a different crank.

I dont want to tell where I race at just yet. I will tell ya it is Alabama

 

You won't want to use 6.0 heads on a 5.3 - the chambers are too large. I'd go with milled 6.0 iron truck heads. A 6.0 that's .030 over equals 370 cubic inches. Get it around 11:1 and it'll be a stout piece.

 

any particular casting# on the 6.0 cast heads? what is the cubic inch limit on a 6.0 block with aftermarket crank and rods?

 

You can go pretty big with 6.0 blocks 414ish easy.

I was going to suggest you find a 6.0 iron block that is in good shape so you can stay stock bore and stock stroke so you will be 364... only 2ci over. If you get to winning or pulling hard on the competition on the straights, you might get ci checked. Only 2ci over might not throw a flag.

 

The valve stem size is something to look at too. LS engine valve stems are smaller than 11/32.

 

i was talking to a guy in the gas station one day and he told me that they made him go in the Big Block class . he had a 408 or 427 i think?

late model

 

It almost looks like the rules are meant to block the use of gen3 engines.

Roller cam, 8mm valve stems, 15 degree aluminum heads, and coil per cylinder ignition with no provisions for a distributor.

It seems to me you are about to go through a whole lotta trouble for them to say "hey, you can't do that".

 

I'm glad someone is here that has the same idea that I do. I'm doing an iron block 5.7L right now that's going in my IMCA/USMTS/UMP type modified. Looks like you're running into some of the same issues I did with the rules, specifically with the camshaft. NOBODY does a cast iron cam core to be able to run it as a flat tappet set-up. My idea was to use a regular hy-roller cam but with some oversized flat tappet lifters that had been chilled/hardened/coated/whatever so they would live on the steel cam. Lots of folks say it won't work, but apparantly the NASCAR boys have it figured out since all the Cup motors are (or were pretty recently) flat tappet.

Good luck with finding the '99-'00 iron 6.0L heads (873 is the casting number), they are very hard to come up with. I got lucky and was able to come up with 2 sets. I seriously doubt any local tech guy is going to know the head is a 15* head, but you can argue that it's a factory mass-produced head and maybe get by with it. As for the valve stem rule, it's no big deal for a machine shop to replace the 8mm guides with some 11/32 guides, just measure the stock valve length and get some new stainless valves in that length and then you'll be able to use standard old-style keepers and retainers when you assemble the heads.

If you go iron-block 5.7L like I'm doing, you'll be under the c.i. limit, I'm going just a few thou. over the stock 5.7 size (piston measures 3.902) so it's only going to be about 347-348ci. We're able to use aluminum heads here but with 25lbs added in front of the motor plate as a penalty, so I'm going to use a set of the DART 225 runner heads on mine. We're turning about 4500-5000rpm at corner exit so we should be right at the beginning of the powerband of the motor with DART heads and the solid roller cam we got spec'd out. Looking at about 76-7800 at the end of the straights.

Good luck if you decide to go this route, but get ready for some sticker shock when you start buying the front end parts for this thing, I've got a lot of $$ wrapped up in just the front distributor mount, water pump, and ATI damper. But luckily these things aren't really "wear" items on the motor and I'll be able to use them for a long time.

If this deal turns out to be a pretty nice motor we're going to run it about the last half of this season and then over the off-season swap out the crank and pistons and build a 383 out of it. Then we'll really be able to have some fun.

 

How about a 5.3 with a "stock" LS7 stroked 4 inch crank. That would put you at 359 inches (approx) and I think they make a distributer/rotor and a high rise intake from GM performance parts. If you could find iron 6.0 heads and mill them to a 70cc chamber, you would have a 10.5 to 1 compression (approx)...........along with the above 11/32 mods to your valvetrain, it might only run you 3-5K for the entire set up

http://store.summitracing.com/partde...9&autoview=sku

 

Driver56 The only thing is the NASCAR boyz aren't running roller cams with flat tappet lifters...the ramp rates are too steep.

 

And the lifters are something like 1" diameter. I've got a SBC now with a mushroom lifter set-up and the face of the lifter is about 0.920 diameter, bigger the lifter face the faster the ramp rates can be. My cam is a solid flat tappet but the lobes look like a roller profile, and we had to spring it like a big hy-roller would be. It's bad *** for a flat tappet set-up.

 

Actually the lifters are much smaller than you think... The smaller the lifter the less valvetrain weight.

 

u could build a 6.0 engine with a 4.8 crank/rods to keep under the ci rule.
using the 6.0 block will allow the use of the gm 99-00 iron heads.
u will be 330-332ci range with .030 overbore

 

I have a set of iron 6.0 heads if anyone is interested....