IMCA Stock Car motor question?

[racer33k]

I race southern sport mods and kinda getting into the stock cars was just wondering what everyones opinions on the motor rule with what would be better?


(A) 350 cfm CARBURETOR ENGINE: No cubic inch or compression limit. Flat tappet cam/lifters and stud-mounted rocker arms only. No shaft or pedestal rocker arms. No titanium engine components. No stud girdles. No mushroom lifters, lifter diameter and configuration must match OEM passenger block. Full roller rocker arms allowed.


(B) 500 cfm CARBURETOR ENGINE: Maximum 361 cubic inches (GM); 363 (Ford); 370 (Chrysler). GM approved block numbers are: 3892657, 3914660, 3914678, 3932388, 3932386, 3956618, 3970000, 3970006, 3970010, 3970014, 10066033, 10066036, 10243880, 14010207, 14010209, 14010287, 14016376, 14016379, 10054727, 14088528, 14088548, 14088552, 14093638, 14101148. Stroke must match block. No 400 or larger cubic inch parts allowed. Violation of cubic inch limit must be verified by removal of head and will result in disqualification, loss of all IMCA points for the season, $1,000 fine and a 30-day suspension. Maximum compression ratio is 10.5 to 1, no tolerance. Flat top or dished pistons only. OEM or OEM replacement steel crankshaft only - cannot be lightened. No aerowing, bullnose, knife edge, undercut or drilling of second or third rod throws. OEM or OEM replacement steel rods only – GM 5.7 or 6-inch rod allowed. Cap screw allowed. Conventional flat tappet cam and lifters only, cannot alter lifter bores. Mandatory one inch inspection hole in all pans – no obstructions to crank and rods. CYLINDER HEADS: Steel only. Must be unaltered approved OEM and original minimum 76 cc combustion chamber. Only GM OEM approved head numbers are: 14079267, 3986336, 3986339, 3986339X, 3986388, 3932441, 376445, 3928454, 3932454, 3876487, 3973487, 3973487X, 3973493, 3951598, 468642, 330862, 333882, 3998920, 3998991, 3998993, 3998997, 3970126. Maximum size valves on these heads are 2.02 inch intake and 1.60 inch exhaust. May use Engine Quest (EQ) Stock Replacement (SR) cylinder head, part number CH350I, head must remain as produced, seat angles and valve sizes can not be changed: three angle valve job only (absolutely no casting removal in valve pocket of EQ head, for any reason). No porting, polishing or unapproved alterations allowed to ANY cylinder head. (Exception is flat milling allowed). Guide plates, screw-in shouldered studs (0.375-inch max) and polylocks allowed. No stud girdles. Full roller rocker arms allowed. GM - 1.250 inch maximum O.D. valve springs, no beehive valve springs allowed. Unaltered OEM type harmonic balancer only

[Verdoorn Racing]

In our area, the 500 carb option dominates. The longer the straightaways, the more dominate that option seems to be.

[let-r-eat]

Track dependent. Small Bullring or long momentum? Weight rule?

[TeamTerminator]

500 carb is the only way to go. There dominating around here. Doesnt matter what size of track either.

[racer33k]

most are 1/4 to 3/8ths dont really know any of them just kinda venturing off up in to kansas to race them.
Do you happen to know what a lot of the guys are doing for trannys? automatics or 3 spds?

[istock11m]

500 carb. Be sure not to get carried away on the cam. Toss up around here on pg's or 3 speed. We run 3 speed.

[dynoman14]

With a 500cfm carb you should be able to build a killer engine. I like the EQ head, you can mill it a good bit and it has good water jackets, decent combustion chamber and flows good and makes good power once you get new seats and a decent valve job in it.

I have built a similar non IMCA package but with all the same parts for local pave track and it turns 7200-7500 and makes killer power.

Where is the rule on intake manifold???

Where is the rule on camshaft???

What are the carburetor rules??? 4412 only or HP metering blocks allowed???