OLD Modified Corvettes

randy wilson · 12-19-2013, 12:14 PM

Ok, Here goes. CLASS: ECONO MOD
81 and older cars. No front wheel drive conversions.
9 lbs. per C.I.D.
Min. wt. 3,000 lbs.
Max. 1 750 cfm carb. Choke horn must remain. Baseplate standard 750.
Ford, Mopar, and GM only. Brodix spec head. Only mods allowed angle milling, and polishing combustion chamber. 11\32 valve min. 2.08 max. Titanium allowed.
Cast intake generally available. No external mods. Max 2" spacer.
Any piston, any rod, any crank, any ring package, any bore, any stroke.
No vac pumps, external oil pumps, belt drives, or internal billet pumps allowed.
No computers allowed.
No titanium, or carbon fiber driveline parts allowed, except carbon fiber drive shaft for safety reasons.
Max. 1 clutch disc, no smaller then 10.5 inch. No counter wts. allowed.
Max. primary tube size on header 2". No more then 2 steps on header.
Motor plates allowed.
Cool can allowed.
SpecC-12 VP fuel
Cam lift .750 max at the valve.
Stud mount rockers only, except Mopar.
14.32 max tire size.
Wheelie wheels permitted.
Max
RPM chip allowed. No other chips allowed.
Play back tach allowed.
Maximum 5 forward gears. CLUTCH MUST BE USED IN ALL 5 GEARS IN THE TRUE CONVENTIONAL MANNER.
Removable tunnel allowed.
No more then 50\50 wt transfer.
.4 pro tree only.
Cam must be in stock location, remain stock diameter for engine used.
Lifters must be stock diameter. Roller cams, and lifters allowed.
Any radiator in stock location.
Engine in stock location, plus, or minus 1"
Distributor must remain in stock location.
Crank trigger allowed.
Any head under suspicion must be sent to Brodix, and $500 fee put up for the expense of protested.
After market balancers required. Min, 8 pt cage. (up to NHRA)
1" site plug required in oil pan to inspect pump.
.Autos remove 100 lbs. Must still maintain min wt.

joespanova · 12-19-2013, 02:39 PM

Those rules have to be changed to suit this , or I can't possibly sign off on them

Dick Butler · 12-19-2013, 02:43 PM

Excellent. Question about cheaper short block might be Sight hole to observe Stock type crank and rods?(No aluminum rods,use nhra accepted rod for motor.)No Knife edge, no odd metal crank. Is this worth it?

randy wilson · 12-19-2013, 02:47 PM

Dick, Joe, discuss. I'm open to anything. We had to start somewhere.Also, I see nothing wrong with that car. Allow 2 fours, and add wt.

Mike Taylor 3601 · 12-19-2013, 04:41 PM

Dick,
I agree with you on keeping cranks from getting crazy,alum rod I don't see as issue,a good high quality steel rod cost more than alum rod does,so don't see it as money issue,personally if this class existed,and I was'nt allowed alum. rod I would probaly spend $300-500 more on steel rods I would trust @RPM I would be cranking.
Randy,
Stud mounted rockers vs.shaft are toss up, if starting with nothing cost is not much different,on these engines shafts would not be expensive,first off no offsets would be need so that cost less. Shafts are easier to get on engine like we are talking about if has long valves ,stud mounted have to buy $400.00 ish rocker that has clearance for anything over 1.500 spring or clearance some that cost 250 ish then add 75ish for best arp stud,150-250 for stud girdle,you are right at shaft price.

One thing that could be possibly good ideal is limit lift @ valve to .630-.660 lift that eliminates reason for having valves over .100 longer,don't need all the extra installed height to get springs on heads that will work with bigger lifts,and that eliminates problems of getting rockers to work. If you ever have put .200-.300 longer valves in sbc w/stud rockers you know what I talking about,as rocker is higher up stud,pushrods get longer, rocker body gets closer to retainers,roller gets moved to outside tip of valve,this also happen on shafts,but all you do is get set of stands that moves rocker back toward intake,and has material added to bottom of stand so you don't need .150'' worth of shims.

Also if shafts was allowed that would be level for all three brands on valvetrains.
All rules look good to me,I would maybe add if not covered,material, bore spacing,deck height, maybe say deck has to be 9.00-9.500 that will cover sbc,mopar,and ford,or some how keep short deck exotic stuff out. I know this elimnates 8.200 (302) based windsor,but it's is probaly too short and could give advantage of lighter rotating assm to that combo over the others.
Mike Taylor 3601

randy wilson · 12-19-2013, 05:37 PM

Mike, I actually agree with all your points. I spent $2,600 on a set of steel rods, and I actually think aluminum rods are easier on parts. I love shaft rockers. I just didn't want people to think this is just about me. Blocks, a very good point made. Min. Deck, say 9". Cams, name your poison. I'm game for anything. Cranks, again, whatever works for me just so we make tear down easy.

Bruce Fulper · 01-07-2022, 11:36 PM

Quote:

Originally Posted by randy wilson

Ok, Here goes. CLASS: ECONO MOD
81 and older cars. No front wheel drive conversions.
9 lbs. per C.I.D.
Min. wt. 3,000 lbs.
Max. 1 750 cfm carb. Choke horn must remain. Baseplate standard 750.
Ford, Mopar, and GM only. Brodix spec head. Only mods allowed angle milling, and polishing combustion chamber. 11\32 valve min. 2.08 max. Titanium allowed.
Cast intake generally available. No external mods. Max 2" spacer.
Any piston, any rod, any crank, any ring package, any bore, any stroke.
No vac pumps, external oil pumps, belt drives, or internal billet pumps allowed.
No computers allowed.
No titanium, or carbon fiber driveline parts allowed, except carbon fiber drive shaft for safety reasons.
Max. 1 clutch disc, no smaller then 10.5 inch. No counter wts. allowed.
Max. primary tube size on header 2". No more then 2 steps on header.
Motor plates allowed.
Cool can allowed.
SpecC-12 VP fuel
Cam lift .750 max at the valve.
Stud mount rockers only, except Mopar.
14.32 max tire size.
Wheelie wheels permitted.
Max
RPM chip allowed. No other chips allowed.
Play back tach allowed.
Maximum 5 forward gears. CLUTCH MUST BE USED IN ALL 5 GEARS IN THE TRUE CONVENTIONAL MANNER.
Removable tunnel allowed.
No more then 50\50 wt transfer.
.4 pro tree only.
Cam must be in stock location, remain stock diameter for engine used.
Lifters must be stock diameter. Roller cams, and lifters allowed.
Any radiator in stock location.
Engine in stock location, plus, or minus 1"
Distributor must remain in stock location.
Crank trigger allowed.
Any head under suspicion must be sent to Brodix, and $500 fee put up for the expense of protested.
After market balancers required. Min, 8 pt cage. (up to NHRA)
1" site plug required in oil pan to inspect pump.
.Autos remove 100 lbs. Must still maintain min wt.

What? No Pontiacs? I have a 326 that will pop your eyeballs out. Would I get to use Edlebrock heads? Or a factory head? I prefer the factory head.

Doug Walker · 01-08-2022, 03:44 AM

Quote:

Originally Posted by Bruce Fulper

What? No Pontiacs? I have a 326 that will pop your eyeballs out. Would I get to use Edlebrock heads? Or a factory head? I prefer the factory head.

Bruce Fulper : Please help me out. What does your post have to do with old modified Corvettes? Admittedly, I just take pictures. I am not a racer. I am not an engine builder. Seems that I am not understanding something.

Bruce Fulper · 01-08-2022, 06:52 PM

Quote:

Originally Posted by Doug Walker

Bruce Fulper : Please help me out. What does your post have to do with old modified Corvettes? Admittedly, I just take pictures. I am not a racer. I am not an engine builder. Seems that I am not understanding something.

Because........there are posts and talking that include guys that have other cars, not 'vettes, they've posted that they'd like to be involved too. Some of the posts put up even suggest potential rules to include Fords and Mopars.

THAT, my dear friend is what caused me to want to possibly jump in the fray too. :-)

I'm fond of heads-up competition. These M/P ideas get me excited. Fun stuff.

Happy New Year!

bubski · 01-08-2022, 02:36 PM

Quote:

Originally Posted by Bruce Fulper

What? No Pontiacs? I have a 326 that will pop your eyeballs out. Would I get to use Edlebrock heads? Or a factory head? I prefer the factory head.

WHOA !!!! Bubski can see the reefer smoke from here as this post was being written !!! Even in todays make no sense world Bubski can't imagine how this relates to modified Vettes !! Bubski recomends taking your one hitter over to the lifter debacle thread !!! Cheers

12-19-2013, 12:14 PM	#1
randy wilson Senior Member Join Date: Jan 2007 Location: N/A Posts: 882 Likes: 0 Liked 22 Times in 22 Posts	Re: OLD Modified Corvettes Ok, Here goes. CLASS: ECONO MOD 81 and older cars. No front wheel drive conversions. 9 lbs. per C.I.D. Min. wt. 3,000 lbs. Max. 1 750 cfm carb. Choke horn must remain. Baseplate standard 750. Ford, Mopar, and GM only. Brodix spec head. Only mods allowed angle milling, and polishing combustion chamber. 11\32 valve min. 2.08 max. Titanium allowed. Cast intake generally available. No external mods. Max 2" spacer. Any piston, any rod, any crank, any ring package, any bore, any stroke. No vac pumps, external oil pumps, belt drives, or internal billet pumps allowed. No computers allowed. No titanium, or carbon fiber driveline parts allowed, except carbon fiber drive shaft for safety reasons. Max. 1 clutch disc, no smaller then 10.5 inch. No counter wts. allowed. Max. primary tube size on header 2". No more then 2 steps on header. Motor plates allowed. Cool can allowed. SpecC-12 VP fuel Cam lift .750 max at the valve. Stud mount rockers only, except Mopar. 14.32 max tire size. Wheelie wheels permitted. Max RPM chip allowed. No other chips allowed. Play back tach allowed. Maximum 5 forward gears. CLUTCH MUST BE USED IN ALL 5 GEARS IN THE TRUE CONVENTIONAL MANNER. Removable tunnel allowed. No more then 50\50 wt transfer. .4 pro tree only. Cam must be in stock location, remain stock diameter for engine used. Lifters must be stock diameter. Roller cams, and lifters allowed. Any radiator in stock location. Engine in stock location, plus, or minus 1" Distributor must remain in stock location. Crank trigger allowed. Any head under suspicion must be sent to Brodix, and $500 fee put up for the expense of protested. After market balancers required. Min, 8 pt cage. (up to NHRA) 1" site plug required in oil pan to inspect pump. .Autos remove 100 lbs. Must still maintain min wt. __________________ don,t have one Last edited by randy wilson; 12-19-2013 at 12:16 PM.

12-19-2013, 02:39 PM	#2
joespanova Senior Member Join Date: Jun 2011 Location: Ga. Posts: 521 Likes: 7 Liked 13 Times in 11 Posts	Re: OLD Modified Corvettes Those rules have to be changed to suit this , or I can't possibly sign off on them

12-19-2013, 02:43 PM	#3
Dick Butler VIP Member Join Date: Oct 2002 Location: Richmond Indiana Posts: 1,196 Likes: 5 Liked 32 Times in 19 Posts	Re: OLD Modified Corvettes Excellent. Question about cheaper short block might be Sight hole to observe Stock type crank and rods?(No aluminum rods,use nhra accepted rod for motor.)No Knife edge, no odd metal crank. Is this worth it?

12-19-2013, 02:47 PM	#4
randy wilson Senior Member Join Date: Jan 2007 Location: N/A Posts: 882 Likes: 0 Liked 22 Times in 22 Posts	Re: OLD Modified Corvettes Dick, Joe, discuss. I'm open to anything. We had to start somewhere.Also, I see nothing wrong with that car. Allow 2 fours, and add wt. __________________ don,t have one

12-19-2013, 04:41 PM	#5
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,369 Likes: 348 Liked 293 Times in 101 Posts	Re: OLD Modified Corvettes Dick, I agree with you on keeping cranks from getting crazy,alum rod I don't see as issue,a good high quality steel rod cost more than alum rod does,so don't see it as money issue,personally if this class existed,and I was'nt allowed alum. rod I would probaly spend $300-500 more on steel rods I would trust @RPM I would be cranking. Randy, Stud mounted rockers vs.shaft are toss up, if starting with nothing cost is not much different,on these engines shafts would not be expensive,first off no offsets would be need so that cost less. Shafts are easier to get on engine like we are talking about if has long valves ,stud mounted have to buy $400.00 ish rocker that has clearance for anything over 1.500 spring or clearance some that cost 250 ish then add 75ish for best arp stud,150-250 for stud girdle,you are right at shaft price. One thing that could be possibly good ideal is limit lift @ valve to .630-.660 lift that eliminates reason for having valves over .100 longer,don't need all the extra installed height to get springs on heads that will work with bigger lifts,and that eliminates problems of getting rockers to work. If you ever have put .200-.300 longer valves in sbc w/stud rockers you know what I talking about,as rocker is higher up stud,pushrods get longer, rocker body gets closer to retainers,roller gets moved to outside tip of valve,this also happen on shafts,but all you do is get set of stands that moves rocker back toward intake,and has material added to bottom of stand so you don't need .150'' worth of shims. Also if shafts was allowed that would be level for all three brands on valvetrains. All rules look good to me,I would maybe add if not covered,material, bore spacing,deck height, maybe say deck has to be 9.00-9.500 that will cover sbc,mopar,and ford,or some how keep short deck exotic stuff out. I know this elimnates 8.200 (302) based windsor,but it's is probaly too short and could give advantage of lighter rotating assm to that combo over the others. Mike Taylor 3601

12-19-2013, 05:37 PM	#6
randy wilson Senior Member Join Date: Jan 2007 Location: N/A Posts: 882 Likes: 0 Liked 22 Times in 22 Posts	Re: OLD Modified Corvettes Mike, I actually agree with all your points. I spent $2,600 on a set of steel rods, and I actually think aluminum rods are easier on parts. I love shaft rockers. I just didn't want people to think this is just about me. Blocks, a very good point made. Min. Deck, say 9". Cams, name your poison. I'm game for anything. Cranks, again, whatever works for me just so we make tear down easy. __________________ don,t have one Last edited by randy wilson; 12-19-2013 at 05:39 PM.