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Author Topic:   9 to 1 Question
HarrisMod#30
Dirt Freak

Total posts: 353
posted September 26, 2005 07:35 PM  
I was just curious about the sportmod motor, what could one expect for horsepower on a 9 to 1 enigine....rules state....
engine #1
fuel system...
Claim engine must use one of three I.M.C.A. approved naturally aspirated carburetors: OEM GM Rochester two barrel carburetor (only alterations allowed are booster I.D. may be machined to .250-inch and venturi I.D. machined to 1.375-inch); Unaltered 350 c.f.m. Holley - part no. 0-7448 or Unaltered 500 c.f.m. Holley - part no. 0-4412, both may be modified to Dorton specs only.
engine specs....
(B) Claim engine with following specs; OEM cast iron, V-8 small-block Chevrolet only. Maximum 9 to 1 compression and 361 cubic inch limit. Must be 3.48-inch stroke and 4.060-inch maximum bore. Track has option to enforce these restrictions with a WHISTLER compression gauge and a cubic inch pump gauge, or by visually checking parts and part numbers. All engines must be able to be used in conventional passenger car without alterations. External engine casting and threaded holes cannot be altered. COMPONENT GUIDELINES: Must use one of following blocks, 3892657, 3914678, 3932388, 3932386, 3956618, 3970000,3970006, 3970010, 3970014, 10066033, 10066036, 14010207, 14010209, 14010287, 14016376, 14016379. Must use one of the following unaltered OEM cylinder heads 330862, 333882, 3876487, 3932441, 3951598, 3970126, 3973493, 3986336, 3998920, 3998993, 3998997. 1.94-inch intake valves and 1.50-inch exhaust valves only. Studs may be pinned or use non-shouldered screw in type. May use stamped steel roller tip rocker arms and polylocks. Must use unaltered approved OEM cast iron two or four barrel intake, or Weiand 7547-1 ‘I.M.C.A. stamped’ intake. No hi-rise or marine intake manifolds. No porting, polishing or alterations of any kind to intake or heads, disqualification and $250 fine if illegal. Flat top or dished pistons only. Must use flat tappet cam and lifters. No mushroom lifters. Cannot alter lifter bores. May use oil restrictors.

How much horsepower could a person expect from on of these motors with the carbs they mention? I am just wondering what to use for a motor, the crate engine a guy could run has 350 horse and it says you can run any 4 barrel holley carb, Which one would give a guy more bang?

[This message has been edited by HarrisMod#30 (edited September 26, 2005).]

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted September 26, 2005 10:22 PM  
They are pretty even... I've heard of 400 hp... and 330 Hp... It's a toss up really. I'd opt for building my own.

midmod34
Dirt Maniac

Total posts: 119
posted September 27, 2005 03:44 PM  
a good motor will do 330 -350 real hp people that are showing 400+ probably slowed the dyno down or fiddled with the barometer readings these are just a couple of ways to bolster the dyno numbers.

HarrisMod#30
Dirt Freak

Total posts: 353
posted September 27, 2005 04:23 PM  
ok thanks guys, so it looks like the crate motor would be ok then? Ill prolly get a crate motor and have some sort of special motor built.

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted September 27, 2005 04:50 PM  
I know how to fiddle with Dyno's and I can't say they did anything different. Just a lot of money wrapped up in the motor. Crate motors are ok, but remember... you break it, you can't fix it.

HarrisMod#30
Dirt Freak

Total posts: 353
posted September 27, 2005 04:57 PM  
yes, excellant point about fixing it, so imca doesnt have any authorized dealers to fix these things?

racer17j
Dirt Forum Champ
Total posts: 5390
posted September 27, 2005 07:26 PM  
No re-build centers. I do know of a shop that I can send my Crate to (Per say if I bought one to run but I won't) and have them tear it down and spruce it up a bunch, put it back together with sealed bolts and wha la...

HarrisMod#30
Dirt Freak

Total posts: 353
posted September 29, 2005 03:51 PM  
out of curiosity, with these smaller 9 to 1 motors what gear would a guy run compared to a regular mod? For example on a half mile we generaly run a 500 gear and turn our mod 7800 rpms, now granted im not gonna wanna turn one of these 9 to 1s that hard and i know the power isnt gonna come on as fast, so would running about the same gear sound right? Also what are we looking at turning one of these things??? 6500 rpm or is that to much?
Thanks guys! Whats the name of that shop extreme...lol j\k

Wildside17
Dirt Maniac

Total posts: 119
posted September 30, 2005 06:50 PM  
Harrismod#30, I've been running 550 on a half this summer. Alot of the guys have been in the same area around 543. Cannot tell you the rpm's cause I threw my tach out after last year.

[This message has been edited by Wildside17 (edited September 30, 2005).]

racer17j
Dirt Forum Champ
Total posts: 5390
posted October 02, 2005 08:11 PM  
thanks guys.

sixmod
Dirt Roller

Total posts: 19
posted October 03, 2005 11:22 PM  
around our area most run 5.29 on half mile works good

Xtreme12x
Dirt Forum Champ
Total posts: 874
posted October 05, 2005 10:59 AM  
Sent you a PM Harrismod... let me know if you got it.

HarrisMod#30
Dirt Freak

Total posts: 353
posted October 05, 2005 03:09 PM  
yep i got it.

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