Cam selection - The 1947 - Present Chevrolet & GMC Truck Message Board Network

my 85 gmc · 01-11-2003, 04:03 AM

I know the question might I'am about to ask may be a low-performance question to you high-performance guys!
I'am considering swapping cams in my 85 GMC which has a LE9 305ci motor since it has less then 50,000 original miles only current mods are dual exhaust with H-pipe and free flow mufflers.

The cam suggested by the Comp Cams rep and my Comp Cams dealer is the Extreme Energy XE250H-10 is this a good choice?
Comp Cams specs:
Duration@ .050": Intake-206 Exhaust-212
Lift: Intake- .432 Exhaust-.444

Stock cam specs

as listed in Year One catalog)
Duration@ .050": Intake-202 Exhaust-206
Lift Intake-.403 Exhaust- .414

Thanks rob

78ls9silvrdo4x4 · 01-11-2003, 06:58 AM

i recently replaced the cam and carb on a 84 305, and used a speedpro, factory blueprint cam for a 350hp/327, it is a solid cam choice if you want some extra bump in your step, they also make a factory blueprint 300hp/327 cam that will work nice too, the cam you mentioned is about a step over stock, and wont be a very noticeable change, but you may notice the diff in fuel consumption, if it were me i'd opt for the 300hp/327 foctory blueprint. either way you go, would be a good "freshen" up cam grind. good luck feel free to ask more questions if you get stuck

low 84 · 01-11-2003, 12:14 PM

78ls - how are you able to make the power posted in your sig with those small valve heads?

Tom · 01-11-2003, 04:59 PM

Quote:

Originally posted by low 84
78ls - how are you able to make the power posted in your sig with those small valve heads?

He didnt. I wont believe that much power until I see a dyno sheet. If I see a dyno sheet, then Ill be very impressed.

As for the cam, its a good choice. Very mild, but better then stock. Every cam spec Ive seen for our trucks is about 196/202 duration and .398/.410 lift or somthing extremly close to that. I do remember the intake duration under a two hundred and its lift under .400"

I would stay away from the old blueprint cams. They are 30 year old designs. A lot has changed since then, and there are MUCH better designs out.

78ls9silvrdo4x4 · 01-13-2003, 12:53 AM

there are quite a few hours of porting and polishing, in the intake as well as the heads, not to mention the carter is no where near stock, i would give the hours in each , but that i just cant do, my machinest has been building race and pull'in engines for about 25years, and doesnot devoulge that info to even myself.and i will get a copy of the dyno sheet as soon as i can get it scanned and loaded,

01-11-2003, 04:03 AM	#1
my 85 gmc Registered User Join Date: Jan 2003 Location: Moncton New Brunswick Posts: 56	Cam selection I know the question might I'am about to ask may be a low-performance question to you high-performance guys! I'am considering swapping cams in my 85 GMC which has a LE9 305ci motor since it has less then 50,000 original miles only current mods are dual exhaust with H-pipe and free flow mufflers. The cam suggested by the Comp Cams rep and my Comp Cams dealer is the Extreme Energy XE250H-10 is this a good choice? Comp Cams specs: Duration@ .050": Intake-206 Exhaust-212 Lift: Intake- .432 Exhaust-.444 Stock cam specsas listed in Year One catalog) Duration@ .050": Intake-202 Exhaust-206 Lift Intake-.403 Exhaust- .414 Thanks rob

01-11-2003, 06:58 AM	#2
78ls9silvrdo4x4 Registered User Join Date: Jan 2003 Location: lost in mo Posts: 22	re:cam selection i recently replaced the cam and carb on a 84 305, and used a speedpro, factory blueprint cam for a 350hp/327, it is a solid cam choice if you want some extra bump in your step, they also make a factory blueprint 300hp/327 cam that will work nice too, the cam you mentioned is about a step over stock, and wont be a very noticeable change, but you may notice the diff in fuel consumption, if it were me i'd opt for the 300hp/327 foctory blueprint. either way you go, would be a good "freshen" up cam grind. good luck feel free to ask more questions if you get stuck __________________ 78 LS9 355, 10.5:1, customground intake 53,000vlt ign, "pink rods" 298h brute trque cam, melling h/v oilpmp carter795cmf afb comp carb taylor wires bosch plugs, carter mech feulpmp 1.94/1.60 lead/sulfer heads w/3angle valve job 1 pc manley valves. .

01-11-2003, 12:14 PM	#3
low 84 Registered User Join Date: Jan 2002 Location: Houston, TX Posts: 2,144	78ls - how are you able to make the power posted in your sig with those small valve heads? __________________ '51 F100, backhalf with a narrowed 9 and coil overs, 18.5" mickeys, monte front clip, +400" sbc in the works '05 1500 Crew Cab RIP '84 swb 5/7 drop, solid cammed 408 w/ fully ported dart heads, th350 w/ 10 inch hughes, 12 bolt w/ 3.73 richmonds and a locker '80 swb 4x4 in progress: 7" lift, 350 th350/np205, d44 and 1.5" ORD tie rod, 14BFF w/discs , armored diff covers, 40" MTR's

01-13-2003, 12:53 AM	#5
78ls9silvrdo4x4 Registered User Join Date: Jan 2003 Location: lost in mo Posts: 22	there are quite a few hours of porting and polishing, in the intake as well as the heads, not to mention the carter is no where near stock, i would give the hours in each , but that i just cant do, my machinest has been building race and pull'in engines for about 25years, and doesnot devoulge that info to even myself.and i will get a copy of the dyno sheet as soon as i can get it scanned and loaded, __________________ 78 LS9 355, 10.5:1, customground intake 53,000vlt ign, "pink rods" 298h brute trque cam, melling h/v oilpmp carter795cmf afb comp carb taylor wires bosch plugs, carter mech feulpmp 1.94/1.60 lead/sulfer heads w/3angle valve job 1 pc manley valves. .

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.