Bracket Talk
Headhunter 395 MC on alcohol?
June 12, 2023, 02:00 PM
TOP38Headhunter 395 MC on alcohol?
quote:
Originally posted by Doug:
quote:
Originally posted by 329L:
If you dont have atleast a 308 exhaust lobe, and a 115 centerline, nothing will prolly fix it. I have an alky injected 632 with profiler 174x, with ti valves, and it takes autolight 3934 or ngk -8 to keep it lit. -9 plug will miss when up stairs.
Spread port heads need more EX duration than conventional heads to start with... 296 is small though, what's the intake lobe?
Also what are your goals for this combo power wise? Gas will make more power but if that's not a concern alky will work. What's your piston to head clearance also?
296 @ .050, 114 centerline
June 12, 2023, 02:10 PM
HalverstadtI have two 632 engines with the Brodix 395mc Head Hunters; running this combination going on almost 10 years now. It has proved to be a (relatively) fast and reliable conventional headed set up over the years.
Both engines are:
-Tunnel Ram with (2) alcohol 4150 APD 950's
-Runs best ET at 36* timing
-E3 -9 projected tip spark plugs (Have also used NGK -9pt) Don't have to index the E3's and they perform just as well.
-15:1 Compression, .908 lift cam
-MSD 7720 + 7730 and 8261 Coil
-Ron's Injection "1/2 pump" mechanical fuel pump, 3lbs at idle and 9lbs going down the track.
I would consider the MSD 7720, or MSD 8 / 10 ignition box with MSD 8261 coil to adequately burn the fuel if you haven't already.
Otherwise you may look into a mechanical fuel pump or doing a true A-B test with a different alcohol carburetor. I believe both of us would be faster on gas, but you can certainly make the combination dependable on alcohol in my experience. Don't give up!
June 12, 2023, 02:20 PM
329L296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
Jeremiah Hall
June 12, 2023, 02:32 PM
Lenny5160quote:
Originally posted by 329L:
296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
This isn't my thread, but my 632 with the same basic issue is 297 @ .050 on the exhaust side with 114 LSA, so I can believe that you're on to something.
Tony Leonard
June 12, 2023, 02:33 PM
TOP38quote:
Originally posted by 329L:
296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
My bad, I know that head also. My 565 had 284/300 on a 112 if I remember correctly.
June 12, 2023, 02:34 PM
TOP38quote:
Originally posted by 329L:
296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
What's your piston to head clearance?
June 12, 2023, 02:51 PM
Dougquote:
Originally posted by TOP38:
quote:
Originally posted by Doug:
quote:
Originally posted by 329L:
If you dont have atleast a 308 exhaust lobe, and a 115 centerline, nothing will prolly fix it. I have an alky injected 632 with profiler 174x, with ti valves, and it takes autolight 3934 or ngk -8 to keep it lit. -9 plug will miss when up stairs.
Spread port heads need more EX duration than conventional heads to start with... 296 is small though, what's the intake lobe?
Also what are your goals for this combo power wise? Gas will make more power but if that's not a concern alky will work. What's your piston to head clearance also?
296 @ .050, 114 centerline
it made 1146hp, 940ft lb on the dyno with a house 1250 on 112 gas, I'm ok with those numbers so I will stick with gas and maybe look into a cam swap next year
June 12, 2023, 03:00 PM
329Lquote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
What's your piston to head clearance?
.130 ish, and i still have 15.2 compression
Jeremiah Hall
June 12, 2023, 03:01 PM
329Lquote:
Originally posted by Doug:
quote:
Originally posted by TOP38:
quote:
Originally posted by Doug:
quote:
Originally posted by 329L:
If you dont have atleast a 308 exhaust lobe, and a 115 centerline, nothing will prolly fix it. I have an alky injected 632 with profiler 174x, with ti valves, and it takes autolight 3934 or ngk -8 to keep it lit. -9 plug will miss when up stairs.
Spread port heads need more EX duration than conventional heads to start with... 296 is small though, what's the intake lobe?
Also what are your goals for this combo power wise? Gas will make more power but if that's not a concern alky will work. What's your piston to head clearance also?
296 @ .050, 114 centerline
it made 1146hp, 940ft lb on the dyno with a house 1250 on 112 gas, I'm ok with those numbers so I will stick with gas and maybe look into a cam swap next year
It will most likely be atleast .1 quicker on gas, and should run decent. I know alot of gas engines that run as much duration as well, and every one of them FLIES!
Jeremiah Hall
June 12, 2023, 03:03 PM
329Lquote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
My bad, I know that head also. My 565 had 284/300 on a 112 if I remember correctly.
Bet that s.o.b. ran damn good too!
Jeremiah Hall
June 12, 2023, 03:05 PM
wideopen231Question. Remember it is coming from injection only for 37 years.
I see quite a few post here similar to this. Could the problem be that with the size of the carb regulates the amount of air available? That with the amount of alcohol, it takes to feed the motor. It simply does not get enough air to mix with amount of fuel you need to run the engine of this power range. Almost twice the fuel takes up a lot of space in runners and ports. How much air space is left?
Just wondering. Has anyone run the same combo with injection or dual carbs?
America home of free. Brought to you by 2nd amendment.
June 12, 2023, 03:07 PM
wideopen231You have 1250 cfm. I think that is same as the smallest toilet Rons sells. Would run the smallest on this motor?
America home of free. Brought to you by 2nd amendment.
June 12, 2023, 03:11 PM
TOP38quote:
Originally posted by 329L:
quote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
What's your piston to head clearance?
.130 ish, and i still have 15.2 compression
Another alky key with a large motor and lost of fuel needed! These need more piston to head clearance! Some combos need softened chambers too.
June 12, 2023, 03:12 PM
TOP38quote:
Originally posted by 329L:
quote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
My bad, I know that head also. My 565 had 284/300 on a 112 if I remember correctly.
Bet that s.o.b. ran damn good too!
7.20's/184 plus at 1930 lbs.
June 12, 2023, 03:13 PM
329Lquote:
Originally posted by wideopen231:
Question. Remember it is coming from injection only for 37 years.
I see quite a few post here similar to this. Could the problem be that with the size of the carb regulates the amount of air available? That with the amount of alcohol, it takes to feed the motor. It simply does not get enough air to mix with amount of fuel you need to run the engine of this power range. Almost twice the fuel takes up a lot of space in runners and ports. How much air space is left?
Just wondering. Has anyone run the same combo with injection or dual carbs?
My combo is injected. And when i tried to run a cam with a 298 exhaust lobe, the DRAGSTER would only run 4.68-4.72....year round. Put the 308 cam in it, and it immediately went into low 60s, then i was able to put more fuel to it, and it went into the .50s.
Jeremiah Hall
June 12, 2023, 03:17 PM
329Lquote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
quote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
My bad, I know that head also. My 565 had 284/300 on a 112 if I remember correctly.
Bet that s.o.b. ran damn good too!
7.20's/184 plus at 1930 lbs.
Damn, and my combo goes low 7.0s high 6.90s at 186-187 at 1900 lbs. I never race 1320, so i dont try to lean it out when i go yard, but im sure with a lean out, and some tuning, i could get it to go 6.90s most of time. But it runs 4.48-4.58 through the year, so it does everything i want it to do. I do put lifters and springs on it every 200 passes, and only reason i change lifters that often is because i feel lifters do way more damage when failure happens, compared to cost of replacing lifters.
Jeremiah Hall
June 12, 2023, 03:27 PM
wideopen231quote:
Originally posted by 329L:
quote:
Originally posted by wideopen231:
Question. Remember it is coming from injection only for 37 years.
I see quite a few post here similar to this. Could the problem be that with the size of the carb regulates the amount of air available? That with the amount of alcohol, it takes to feed the motor. It simply does not get enough air to mix with amount of fuel you need to run the engine of this power range. Almost twice the fuel takes up a lot of space in runners and ports. How much air space is left?
Just wondering. Has anyone run the same combo with injection or dual carbs?
My combo is injected. And when i tried to run a cam with a 298 exhaust lobe, the DRAGSTER would only run 4.68-4.72....year round. Put the 308 cam in it, and it immediately went into low 60s, then I was able to put more fuel to it, and it went into the .50s.
Alky does burn more fuel so getting it out would require more cam. Only make sense when you think about it. If the cylinder is full of left over it can not get more oxygen-filled air in the hole.
So I take it you kind of agree with my thinking on a carb could be limiting the amount of available air for a needed amount of fuel?
I have always felt that alcohol motors could use larger runners and ports just due to the volume consumed by fuel.
Sorry not trying to derail the thread. Just asking question. If like reply with pm.
America home of free. Brought to you by 2nd amendment.
June 12, 2023, 03:38 PM
TOP38quote:
Originally posted by 329L:
quote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
quote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
My bad, I know that head also. My 565 had 284/300 on a 112 if I remember correctly.
Bet that s.o.b. ran damn good too!
7.20's/184 plus at 1930 lbs.
Damn, and my combo goes low 7.0s high 6.90s at 186-187 at 1900 lbs. I never race 1320, so i dont try to lean it out when i go yard, but im sure with a lean out, and some tuning, i could get it to go 6.90s most of time. But it runs 4.48-4.58 through the year, so it does everything i want it to do. I do put lifters and springs on it every 200 passes, and only reason i change lifters that often is because i feel lifters do way more damage when failure happens, compared to cost of replacing lifters.
I have a 632 SR20 deal now, use Isky Red Zone bushed lifters. Great lifter, in the past I used them in a 12 degree BBC, .848" lifters, over 300 runs and they are like new. I use the 904's in my current motor, over 400 runs and they are like new! On springs, PSI ML's seam to the the best going now.
June 12, 2023, 03:46 PM
329Lquote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
quote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
quote:
Originally posted by TOP38:
quote:
Originally posted by 329L:
296 @ .050 IS why its missing, you cannot get all the spent gasses out, so it misfires. I run a 308 @ .050, and nexxt cam WILL be a 310-312.
top,
my 174x cylinder heads are TRUE CONVENTIONAL heads, not spread ports, not 20 degree, nor is it a rolled head.
My bad, I know that head also. My 565 had 284/300 on a 112 if I remember correctly.
Bet that s.o.b. ran damn good too!
7.20's/184 plus at 1930 lbs.
Damn, and my combo goes low 7.0s high 6.90s at 186-187 at 1900 lbs. I never race 1320, so i dont try to lean it out when i go yard, but im sure with a lean out, and some tuning, i could get it to go 6.90s most of time. But it runs 4.48-4.58 through the year, so it does everything i want it to do. I do put lifters and springs on it every 200 passes, and only reason i change lifters that often is because i feel lifters do way more damage when failure happens, compared to cost of replacing lifters.
I have a 632 SR20 deal now, use Isky Red Zone bushed lifters. Great lifter, in the past I used them in a 12 degree BBC, .848" lifters, over 300 runs and they are like new. I use the 904's in my current motor, over 400 runs and they are like new! On springs, PSI ML's seam to the the best going now.
I WILL be switching back to isky on next freshen....
Jeremiah Hall
June 13, 2023, 05:38 AM
cartmanquote:
Of course it didn’t, typically they have the same throttle bore. Forget claimed CFM, it’s all about throttle bore size. The big power 632’s of friends and competitors have 2.375 throttle bore carbs and they all run gas.
My 1450 has a 2.250 bore. I was thinking the 1250s were 2.125 but I may be wrong.