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. .



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