305/350 head swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

69GMC910 · 07-06-2002, 06:24 PM

I had the 1.72/1.5 58cc chambers on my 350, I just put 350 heads on with 1.94/1.5 valves and a 76cc chamber. What sort of things can I expect to notice: power increase/decrease, peak rpm increase? Torque I or D, mileage up or down, and anything else you can think of is much appreciated!!!

*Fast68Chevy* · 07-06-2002, 06:44 PM

return to stock compression ratio and more air volume admitted into cylinders

Longhorn Man · 07-06-2002, 08:03 PM

WOOO HOOOO!!!! Cheap gas!!!!!! (toss the octain booster and fill up with 87 octain)
Your engine will breathe better, and spin a little easier. Been there, done that.

69GMC910 · 07-07-2002, 12:19 AM

So here is my current setup with the 73 z-28 350, stock in 73 was 245hp, here is what has been done to it:

.030 over
RV cam ( WOO HOO!)
Headman Headers
350 cast heads 1.94/1.5
Edelbrock Performer Intake Manifold
Edelbrock Performer 600cfm man. choke
10:1 Flat Top Pistons
Accel Super Coil, Cap, Rotor and Wires
Bosch Platnium Spark Plugs
Open Air filter 14" by 5"

The truck as I have figured has about 8.9:1 compression. Anybody with a similar setup have any idea what kind of HP this engine puts out? Obviously, dyno would be the best thing, but just a ballpark is all I ask for!

Thanks!!!

mikep · 07-07-2002, 12:22 AM

I guess it would all depend on what an RV cam is. Is that the same as a 3/4 cam ? Whatever that is.

69GMC910 · 07-07-2002, 12:32 AM

An RV cam is so close to stock nowadays that it really isn't something to brag about. They give a little more torque and that's about it.

Longhorn Man · 07-07-2002, 12:32 AM

RV cam isn't nearly as generic as 3/4 cam.
The RV cam is a low end torque cam grind, normally just one or two steps above stck
A 3/4 cam is as generic as a statement can be...may as well call it Bob. What is a full race cam? What kind of race? What kind of engine? What kind of vehicle? What class? Power boosters aloud?
See, there are way too many variables when you use a 'race cam' as a base line.
However, for the best part, stock is stock and you can use that as a base line.

69GMC910 · 07-07-2002, 01:02 AM

Okay, nobody is giving me a horsepower estimate. Is the output of this small block so frightening that you were all scared off before you could type a number!!!

Would 300 hp be pushing it?

Longhorn Man · 07-07-2002, 01:10 AM

get the cam specs, and some one might desk top dyno it.
With out the head casting # it is sorta guessing too.

bigjimzlll · 07-07-2002, 10:58 AM

hope this works

bigjimzlll · 07-07-2002, 11:06 AM

lets try it again( imtrying to import the dyno sheet)..OK THE FILE IS TO BIG..HERE are the numbers...max torque@3250 is 338 and th HP @ 5000 is 281

bigjimzlll · 07-07-2002, 11:09 AM

give me your email address and ill send you the report

mikep · 07-07-2002, 11:26 AM

Hey bigjimzlll.

I'm building a motor up for mine right now. Think you could give me a hand with your mr wizard machine?

compression is 9.5:1

heads are World product S/R ( 76 cc chamber 1.92 intake, 1.5 exhaust )

Performer intake

cam is .420"/.442" lift and 204/214 duration at .050"

750 edelbrock carb

HEI

1.5 inch primary headers into free flowing dual exhaust

my email is mikeandnatasha@charter.net if you feel like doing it .

Thanks

07-06-2002, 06:24 PM	#1
69GMC910 MOTORHEAD! Join Date: May 2000 Location: Devon AB, Canada Posts: 849	305/350 head swap AND a HP question!!! I had the 1.72/1.5 58cc chambers on my 350, I just put 350 heads on with 1.94/1.5 valves and a 76cc chamber. What sort of things can I expect to notice: power increase/decrease, peak rpm increase? Torque I or D, mileage up or down, and anything else you can think of is much appreciated!!! __________________ 82 GMC High Sierra VortecPro 496 12 Bolt, 3.42's AFR 265 Holley 850 Performer RPM Air Gap Hooker 2455's TCI Turbo 400 Super Street Fighter TRRC 12 Bolt Eaton Posi Mark Williams Axles Cal-Tracs Hoosier 30x10.5 Radial Slick Full weight long box pickup Current best- 11.33@117mph Last edited by 69GMC910; 07-07-2002 at 12:33 AM.

07-07-2002, 12:19 AM	#4
69GMC910 MOTORHEAD! Join Date: May 2000 Location: Devon AB, Canada Posts: 849	So here is my current setup with the 73 z-28 350, stock in 73 was 245hp, here is what has been done to it: .030 over RV cam ( WOO HOO!) Headman Headers 350 cast heads 1.94/1.5 Edelbrock Performer Intake Manifold Edelbrock Performer 600cfm man. choke 10:1 Flat Top Pistons Accel Super Coil, Cap, Rotor and Wires Bosch Platnium Spark Plugs Open Air filter 14" by 5" The truck as I have figured has about 8.9:1 compression. Anybody with a similar setup have any idea what kind of HP this engine puts out? Obviously, dyno would be the best thing, but just a ballpark is all I ask for! Thanks!!! __________________ 82 GMC High Sierra VortecPro 496 12 Bolt, 3.42's AFR 265 Holley 850 Performer RPM Air Gap Hooker 2455's TCI Turbo 400 Super Street Fighter TRRC 12 Bolt Eaton Posi Mark Williams Axles Cal-Tracs Hoosier 30x10.5 Radial Slick Full weight long box pickup Current best- 11.33@117mph

07-07-2002, 12:22 AM	#5
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	I guess it would all depend on what an RV cam is. Is that the same as a 3/4 cam ? Whatever that is. __________________ No truck :-(

07-07-2002, 12:32 AM	#6
69GMC910 MOTORHEAD! Join Date: May 2000 Location: Devon AB, Canada Posts: 849	An RV cam is so close to stock nowadays that it really isn't something to brag about. They give a little more torque and that's about it. __________________ 82 GMC High Sierra VortecPro 496 12 Bolt, 3.42's AFR 265 Holley 850 Performer RPM Air Gap Hooker 2455's TCI Turbo 400 Super Street Fighter TRRC 12 Bolt Eaton Posi Mark Williams Axles Cal-Tracs Hoosier 30x10.5 Radial Slick Full weight long box pickup Current best- 11.33@117mph

07-07-2002, 01:02 AM	#8
69GMC910 MOTORHEAD! Join Date: May 2000 Location: Devon AB, Canada Posts: 849	Okay, nobody is giving me a horsepower estimate. Is the output of this small block so frightening that you were all scared off before you could type a number!!! Would 300 hp be pushing it? __________________ 82 GMC High Sierra VortecPro 496 12 Bolt, 3.42's AFR 265 Holley 850 Performer RPM Air Gap Hooker 2455's TCI Turbo 400 Super Street Fighter TRRC 12 Bolt Eaton Posi Mark Williams Axles Cal-Tracs Hoosier 30x10.5 Radial Slick Full weight long box pickup Current best- 11.33@117mph

07-06-2002, 06:44 PM	#2
Fast68Chevy Account Suspended Join Date: May 2000 Location: IL Posts: 0	return to stock compression ratio and more air volume admitted into cylinders

07-06-2002, 08:03 PM	#3
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	WOOO HOOOO!!!! Cheap gas!!!!!! (toss the octain booster and fill up with 87 octain) Your engine will breathe better, and spin a little easier. Been there, done that.

07-07-2002, 01:10 AM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	get the cam specs, and some one might desk top dyno it. With out the head casting # it is sorta guessing too.

07-07-2002, 10:58 AM	#10
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	hope this works __________________ 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

07-07-2002, 11:06 AM	#11
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	lets try it again( imtrying to import the dyno sheet)..OK THE FILE IS TO BIG..HERE are the numbers...max torque@3250 is 338 and th HP @ 5000 is 281 __________________ 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

07-07-2002, 11:09 AM	#12
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	give me your email address and ill send you the report __________________ 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

07-07-2002, 11:26 AM	#13
mikep Used to have a truck Join Date: May 2002 Location: port orchard WA Posts: 1,552	Hey bigjimzlll. I'm building a motor up for mine right now. Think you could give me a hand with your mr wizard machine? compression is 9.5:1 heads are World product S/R ( 76 cc chamber 1.92 intake, 1.5 exhaust ) Performer intake cam is .420"/.442" lift and 204/214 duration at .050" 750 edelbrock carb HEI 1.5 inch primary headers into free flowing dual exhaust my email is mikeandnatasha@charter.net if you feel like doing it . Thanks __________________ No truck :-(



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