engine guys, need more torque on 383 stroker - The 1947 - Present Chevrolet & GMC Truck Message Board Network

matt_field · 07-31-2004, 03:21 PM

i have a 383 stroker in my 67 k10, and its kinda slacking on the get up and go when you get on it from a stop. its got 2.02/1.60 camel back heads fully redone in stainless valves. i put about 1,000 into the heads alone. its got a 600 cfm holley, with a edelbrock performer intake. 2.5 inch corvette ram horms. not sure on the cam but it is loppy. how can i get a little more get up and go out of it. the motor really comes alive when your going then punch it just not from a stop as much thanks

matt

sam's 72 · 07-31-2004, 03:45 PM

What rear gear do you have? What tranny are you running? If it puts you back in the seat from a roll, sounds like you need a lower gear. If you have a auto tranny. Get a stall to match your cam, and get a lower rear gear.
Sam

Shane65 · 07-31-2004, 03:48 PM

What gears in the rearend? How much vacuum at idle? This may give you some insight as to how radical the cam is. Is the accelerator pump pumping and is it enough? Is the vacuum and mechanical advance working on the distributor? 600 cfm/Performer should be responsive at the low end and 2.02 valves aren't too big.

matt_field · 07-31-2004, 04:20 PM

my rear end is 3.73 and my tranny is th350, i have a vacuum gauge in my dash, can i just read that at idle and maybe you guys can give me a better idea of what my cam is ? thanks

matt

sam's 72 · 07-31-2004, 04:22 PM

What size tires are you running on the back? I really don't think it will be posible to tell what lift/duration cam you have by just reading vac. I could be wrong but I can not help you on it. If you have tall back tires, that 3 73 will act like a higher gear.
Sam

matt_field · 07-31-2004, 04:31 PM

the tires i have all around the truck are 32'' bfg all terrain, the truck does maybe run a little rich will that effect anything? i think my carb might need to be adjusted

sam's 72 · 07-31-2004, 05:22 PM

In my opinion. I think you need more gear. 4.11, and or stall converter.

Rdrdave · 07-31-2004, 05:28 PM

I would say 4.11 and hopefully you have 2.5" exhaust. The 4.11s are great for a 32" tire.

charlieo · 07-31-2004, 06:39 PM

I think your cam is too big . Sounds like you get good throttle response once the motor is wound up a little but if you want great torque right off the line that cam is the wrong one. Unless you have alot of compression your cam has too much duration and the lobe centers are too narrow. Call Comp cams or Crane & tell them what u want.

crazy longhorn · 07-31-2004, 06:57 PM

If the cam is too big, faster gears,& bigger carbs will fix it! crazyL

browndawg71 · 07-31-2004, 09:05 PM

lean out the carb if its rich. do you have a stall or not? do you have a tach if so look and get the right stall for your rpm . a stroker should have enough grunt to pull the 373s out if its not to revvy.

matt_field · 07-31-2004, 10:30 PM

ive got the exhaust, my rear end needs to be gone threw anyways, its soooo noisy. also i was kinda thinking the cam should be replaced this winter. thanks for all your input

matt

bigjimzlll · 07-31-2004, 10:57 PM

A proper tune up can go a long way to wake up a sluggish engine....a long way

Blazer1970 · 08-01-2004, 07:58 AM

Quote:

Originally Posted by bigjimzlll

A proper tune up can go a long way to wake up a sluggish engine....a long way

Yup, how much have you played with the timing?

1BadSS · 08-01-2004, 08:02 AM

it's a 4x4, they arent meant to jump off the line. If you want a race truck, get a 2wd

matt_field · 08-01-2004, 01:10 PM

i never said it was a race truck, itd just like to get some more torque out of it. timing is screwed on this truck, listen to this you have to get it PERFECT or the thing will act like it has a dead battery, or it will ping like crazy. i had to play with it for like a day to get it so it starts and doesnt ping, its weird my distributer is a mallory unilite with a promaster coil if that makes a difference

68C15 · 08-01-2004, 03:39 PM

my personal experience shows that anything with a Mallory name is a waste of time. it is soooo hard to tune around an item that is not consistent. I recommend an HEI with a MSD coil. set timing to 12*, lean idle to point of wanting to die then open up 1/2 turn. if at that time you have a dead spot it is most likely due to large intake volume which needs larger acc spray. (not longer)
do you have a way to test exh backpressure? if it is over 2 pounds @ 2000 rpm that will cause a problem with larger cams which will cause it to be rich.

dennis111 · 08-01-2004, 03:54 PM

Does the mallory have vacuum advance or is it just centrifical advance? For best driveability you need the vacuum. I agree that an HEI is a better choice for normal driving.

Other than that it sounds like you might have too much cam for your liking.

matt_field · 08-01-2004, 05:27 PM

my mallory is just centrifical advance, i should try out a hei with a new coil and see how that goes. i have never liked that unilite thanks

matt

Shane65 · 08-01-2004, 07:07 PM

Bingo! You need vacuum advance for street driven vehicles. Non vacuum distributors work well for race vehicles and that's it.

Ogier · 08-01-2004, 09:50 PM

Have you actually tuned your Holley? Personally, I don't think it is cam, timing, CFM, exhaust or anything else that has been mentioned. If you took the holley out of the box and bolted it onto your engine, it is most likely not set up correctly for your engine.

If you have a mechanical secondary carb and an automatic, sell the carb and buy one with vacume secondaries. Then tune.

If you have a vacume secondary carb, it sounds like you need a stronger spring in the vacume chamber that will slow down the openning of the secondaries.

More CFM will make your problem worse, not better. You have the right cfm for your motor. Now just tune the carb.

If you want more info on tuning a Holley, please e-mail me offlist.

Ogier

bigjimzlll · 08-01-2004, 10:35 PM

Quote:

Originally Posted by Ogier

Have you actually tuned your Holley? Personally, I don't think it is cam, timing, CFM, exhaust or anything else that has been mentioned. If you took the holley out of the box and bolted it onto your engine, it is most likely not set up correctly for your engine.

If you have a mechanical secondary carb and an automatic, sell the carb and buy one with vacume secondaries. Then tune.

If you have a vacume secondary carb, it sounds like you need a stronger spring in the vacume chamber that will slow down the openning of the secondaries.

More CFM will make your problem worse, not better. You have the right cfm for your motor. Now just tune the carb.

If you want more info on tuning a Holley, please e-mail me offlist.

Ogier

while I agree that a properly tuned carb is a must...the statement that the 600cfm is the "right" cfm for his engine is a little bold. He has a "lumpy cam" and it is a 383. The carb will work...but it is not optimal for performace. A 4160 would be my cam of choice for his application

Blue4x4 · 08-02-2004, 12:53 AM

I'm using the hei dist on my 383 and no complaints here. 3.73 gears and 4 wheel drive. let us know.

Budweis · 08-02-2004, 01:27 AM

i use a mech mallory unilite and i can roast my tires till they pop if need so i doubt thats the prob. did you try changing the advance with the tool that comes with it? what do you have it set on?

Ogier · 08-02-2004, 01:46 AM

383 cu/in * 4500 RPM /3456 = 498 CFM

Please keep in mind that the intrnal combustion engine is basically an air pump. 600 cfm is taking into account the hypo cam etc.

I used to run a 1968 buick skylark with a stage II 455 putting out 475hp and 550lbs/ft to the ground. I ran a model 1650 600CFM vacume secondary carb on it. There was absolutely no hesitation or boggyness. It would also spin up to 5000rpm between shifts with no trouble.

Anything, and yes, I do mean anything larger than 600 cfm on the street is completely useless in my oppinion. Granted, I am kind of a beginner. I have only built engines for 20 years of all sizes and makes.

Good luck.
Ogier

07-31-2004, 03:21 PM	#1
matt_field Registered User Join Date: Apr 2001 Location: Detroit Lakes, Minnesota Posts: 885	engine guys, need more torque on 383 stroker i have a 383 stroker in my 67 k10, and its kinda slacking on the get up and go when you get on it from a stop. its got 2.02/1.60 camel back heads fully redone in stainless valves. i put about 1,000 into the heads alone. its got a 600 cfm holley, with a edelbrock performer intake. 2.5 inch corvette ram horms. not sure on the cam but it is loppy. how can i get a little more get up and go out of it. the motor really comes alive when your going then punch it just not from a stop as much thanks matt __________________ 1971 k5 blazer 80k mike survivor 1972 3/4 ton 4wd Cummins 12v 1967 swb 2wd 427bbc 1968 4wd shortbox 1971 Cheyenne swb k10 unrestored 1971 Cheyenne super 40k 402bb survivor 1967 Chevy k10 (first truck) 1968 L78 camaro survivor 18k miles 1969 z28 survivor 60k miles 1969 z28 survivor 39k miles 1969 z28 rs survivor 80k miles

07-31-2004, 03:45 PM	#2
sam's 72 Senior Member Join Date: Nov 2001 Location: Pasadena, Texas, USA Posts: 1,005	What rear gear do you have? What tranny are you running? If it puts you back in the seat from a roll, sounds like you need a lower gear. If you have a auto tranny. Get a stall to match your cam, and get a lower rear gear. Sam __________________ 72 LWB chevy truck. Pasadena, Texas

07-31-2004, 03:48 PM	#3
Shane65 Registered User Join Date: Oct 2003 Location: Ontario Posts: 108	What gears in the rearend? How much vacuum at idle? This may give you some insight as to how radical the cam is. Is the accelerator pump pumping and is it enough? Is the vacuum and mechanical advance working on the distributor? 600 cfm/Performer should be responsive at the low end and 2.02 valves aren't too big. Last edited by Shane65; 07-31-2004 at 10:08 PM.

07-31-2004, 04:20 PM	#4
matt_field Registered User Join Date: Apr 2001 Location: Detroit Lakes, Minnesota Posts: 885	my rear end is 3.73 and my tranny is th350, i have a vacuum gauge in my dash, can i just read that at idle and maybe you guys can give me a better idea of what my cam is ? thanks matt __________________ 1971 k5 blazer 80k mike survivor 1972 3/4 ton 4wd Cummins 12v 1967 swb 2wd 427bbc 1968 4wd shortbox 1971 Cheyenne swb k10 unrestored 1971 Cheyenne super 40k 402bb survivor 1967 Chevy k10 (first truck) 1968 L78 camaro survivor 18k miles 1969 z28 survivor 60k miles 1969 z28 survivor 39k miles 1969 z28 rs survivor 80k miles

07-31-2004, 04:22 PM	#5
sam's 72 Senior Member Join Date: Nov 2001 Location: Pasadena, Texas, USA Posts: 1,005	What size tires are you running on the back? I really don't think it will be posible to tell what lift/duration cam you have by just reading vac. I could be wrong but I can not help you on it. If you have tall back tires, that 3 73 will act like a higher gear. Sam __________________ 72 LWB chevy truck. Pasadena, Texas

07-31-2004, 04:31 PM	#6
matt_field Registered User Join Date: Apr 2001 Location: Detroit Lakes, Minnesota Posts: 885	the tires i have all around the truck are 32'' bfg all terrain, the truck does maybe run a little rich will that effect anything? i think my carb might need to be adjusted __________________ 1971 k5 blazer 80k mike survivor 1972 3/4 ton 4wd Cummins 12v 1967 swb 2wd 427bbc 1968 4wd shortbox 1971 Cheyenne swb k10 unrestored 1971 Cheyenne super 40k 402bb survivor 1967 Chevy k10 (first truck) 1968 L78 camaro survivor 18k miles 1969 z28 survivor 60k miles 1969 z28 survivor 39k miles 1969 z28 rs survivor 80k miles

07-31-2004, 05:22 PM	#7
sam's 72 Senior Member Join Date: Nov 2001 Location: Pasadena, Texas, USA Posts: 1,005	In my opinion. I think you need more gear. 4.11, and or stall converter. __________________ 72 LWB chevy truck. Pasadena, Texas

07-31-2004, 05:28 PM	#8
Rdrdave Broke and still trying Join Date: Apr 2003 Location: Alameda, CA Posts: 562	I would say 4.11 and hopefully you have 2.5" exhaust. The 4.11s are great for a 32" tire.

07-31-2004, 06:39 PM	#9
charlieo Registered User Join Date: Feb 2003 Location: sw Posts: 341	I think your cam is too big . Sounds like you get good throttle response once the motor is wound up a little but if you want great torque right off the line that cam is the wrong one. Unless you have alot of compression your cam has too much duration and the lobe centers are too narrow. Call Comp cams or Crane & tell them what u want.

07-31-2004, 06:57 PM	#10
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	If the cam is too big, faster gears,& bigger carbs will fix it! crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

07-31-2004, 09:05 PM	#11
browndawg71 Registered User Join Date: Jun 2004 Location: paris, texas Posts: 235	lean out the carb if its rich. do you have a stall or not? do you have a tach if so look and get the right stall for your rpm . a stroker should have enough grunt to pull the 373s out if its not to revvy.

07-31-2004, 10:30 PM	#12
matt_field Registered User Join Date: Apr 2001 Location: Detroit Lakes, Minnesota Posts: 885	ive got the exhaust, my rear end needs to be gone threw anyways, its soooo noisy. also i was kinda thinking the cam should be replaced this winter. thanks for all your input matt __________________ 1971 k5 blazer 80k mike survivor 1972 3/4 ton 4wd Cummins 12v 1967 swb 2wd 427bbc 1968 4wd shortbox 1971 Cheyenne swb k10 unrestored 1971 Cheyenne super 40k 402bb survivor 1967 Chevy k10 (first truck) 1968 L78 camaro survivor 18k miles 1969 z28 survivor 60k miles 1969 z28 survivor 39k miles 1969 z28 rs survivor 80k miles

07-31-2004, 10:57 PM	#13
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	A proper tune up can go a long way to wake up a sluggish engine....a long way __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

08-01-2004, 08:02 AM	#15
1BadSS NOT REALLY BANNED! Join Date: Jul 2004 Location: Shawnee, KS Posts: 1,072	it's a 4x4, they arent meant to jump off the line. If you want a race truck, get a 2wd __________________ 1987 Mustang Coupe - 2.7 Stroker, 78mm turbo, Stainless header, 3" Exh, FMIC, 160lb/hr Injectors, MS3, twin walbro 255's, 34psi. Eating V8's daily. 04 Pontiac GTO 04 Ford Mustang GT 68 C20 LWB stripper truck 73 K5 Cheyenne 76 C20 Sierra Crew SRW 88 K20 Suburban I'm not hammering on metal just to hammer, i'm creating a piece of art.

08-01-2004, 01:10 PM	#16
matt_field Registered User Join Date: Apr 2001 Location: Detroit Lakes, Minnesota Posts: 885	i never said it was a race truck, itd just like to get some more torque out of it. timing is screwed on this truck, listen to this you have to get it PERFECT or the thing will act like it has a dead battery, or it will ping like crazy. i had to play with it for like a day to get it so it starts and doesnt ping, its weird my distributer is a mallory unilite with a promaster coil if that makes a difference __________________ 1971 k5 blazer 80k mike survivor 1972 3/4 ton 4wd Cummins 12v 1967 swb 2wd 427bbc 1968 4wd shortbox 1971 Cheyenne swb k10 unrestored 1971 Cheyenne super 40k 402bb survivor 1967 Chevy k10 (first truck) 1968 L78 camaro survivor 18k miles 1969 z28 survivor 60k miles 1969 z28 survivor 39k miles 1969 z28 rs survivor 80k miles



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08-01-2004, 03:39 PM	#17
68C15 blood type; Retumbo Join Date: Jan 2004 Location: next to my reloading bench Posts: 10,269	my personal experience shows that anything with a Mallory name is a waste of time. it is soooo hard to tune around an item that is not consistent. I recommend an HEI with a MSD coil. set timing to 12*, lean idle to point of wanting to die then open up 1/2 turn. if at that time you have a dead spot it is most likely due to large intake volume which needs larger acc spray. (not longer) do you have a way to test exh backpressure? if it is over 2 pounds @ 2000 rpm that will cause a problem with larger cams which will cause it to be rich. __________________ Man rule #77...if you own a 67 stepside with a caddy 472 you will never be in danger of loosing you man card

08-01-2004, 03:54 PM	#18
dennis111 Registered User Join Date: Jul 2004 Location: Amish Wonderland of Central PA. Posts: 31	Does the mallory have vacuum advance or is it just centrifical advance? For best driveability you need the vacuum. I agree that an HEI is a better choice for normal driving. Other than that it sounds like you might have too much cam for your liking. __________________ Dennis 68 GMC SWB Custom 1/2 ton, 2WD, 350 V8, PS, PB, 3-Speed, 3:08 12 bolt rear, tilt, tach, vac, cruise and more. . . .

08-01-2004, 05:27 PM	#19
matt_field Registered User Join Date: Apr 2001 Location: Detroit Lakes, Minnesota Posts: 885	my mallory is just centrifical advance, i should try out a hei with a new coil and see how that goes. i have never liked that unilite thanks matt __________________ 1971 k5 blazer 80k mike survivor 1972 3/4 ton 4wd Cummins 12v 1967 swb 2wd 427bbc 1968 4wd shortbox 1971 Cheyenne swb k10 unrestored 1971 Cheyenne super 40k 402bb survivor 1967 Chevy k10 (first truck) 1968 L78 camaro survivor 18k miles 1969 z28 survivor 60k miles 1969 z28 survivor 39k miles 1969 z28 rs survivor 80k miles

08-01-2004, 07:07 PM	#20
Shane65 Registered User Join Date: Oct 2003 Location: Ontario Posts: 108	Bingo! You need vacuum advance for street driven vehicles. Non vacuum distributors work well for race vehicles and that's it.

08-01-2004, 09:50 PM	#21
Ogier Chopper/Painter Join Date: Jul 2004 Location: Medford, Or. Posts: 284	Have you actually tuned your Holley? Personally, I don't think it is cam, timing, CFM, exhaust or anything else that has been mentioned. If you took the holley out of the box and bolted it onto your engine, it is most likely not set up correctly for your engine. If you have a mechanical secondary carb and an automatic, sell the carb and buy one with vacume secondaries. Then tune. If you have a vacume secondary carb, it sounds like you need a stronger spring in the vacume chamber that will slow down the openning of the secondaries. More CFM will make your problem worse, not better. You have the right cfm for your motor. Now just tune the carb. If you want more info on tuning a Holley, please e-mail me offlist. Ogier

08-02-2004, 12:53 AM	#23
Blue4x4 Senior Member Join Date: Mar 2003 Location: Sparks, NV Posts: 790	I'm using the hei dist on my 383 and no complaints here. 3.73 gears and 4 wheel drive. let us know.

08-02-2004, 01:27 AM	#24
Budweis Geared for Collision Join Date: Jan 2004 Location: St. Louis, Mo. Posts: 683	i use a mech mallory unilite and i can roast my tires till they pop if need so i doubt thats the prob. did you try changing the advance with the tool that comes with it? what do you have it set on? __________________ MEMBER OF THE 4 WHEEL DISK BRAKE CLUB 1970 C/K20 3/4 Ton 1996 Collectors Edition Corvette 1977 Corvette Coupe Last edited by Budweis; 08-02-2004 at 01:32 AM.

08-02-2004, 01:46 AM	#25
Ogier Chopper/Painter Join Date: Jul 2004 Location: Medford, Or. Posts: 284	383 cu/in * 4500 RPM /3456 = 498 CFM Please keep in mind that the intrnal combustion engine is basically an air pump. 600 cfm is taking into account the hypo cam etc. I used to run a 1968 buick skylark with a stage II 455 putting out 475hp and 550lbs/ft to the ground. I ran a model 1650 600CFM vacume secondary carb on it. There was absolutely no hesitation or boggyness. It would also spin up to 5000rpm between shifts with no trouble. Anything, and yes, I do mean anything larger than 600 cfm on the street is completely useless in my oppinion. Granted, I am kind of a beginner. I have only built engines for 20 years of all sizes and makes. Good luck. Ogier

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