Topic: crate gm 350 upgrades
in Forum: C3 Engines
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I have a 1971 corvette 4 spd with gm crate motor 10067353 in it. I am looking to get more out of this engine while keeping it streetable. Some people have told me I can change out the heads, intake, and cam and get great results. Others say I should just buy a new engine. I am not a motorhead although I am trying to read as much as possible. If anybody has any experience with modifying engines I would appriciate and information. Thank You for your time..
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Lifetime MemberSHELBYVILLE, TN - USA
Joined: 7/5/2002
Posts: 3942
Vette(s): 1976 L48 auto
1978 L82 4speed
1994 LT1 6speed
1978 L82 4speed
1994 LT1 6speed
Well, what you got there is a 195 hp engine... 4 bolt main, 76cc heads with 1.94 intake, 1.50 exhaust valve, .383 lift intake 194 duration, .401 lift exhaust lift 202 duration, and.. 8.5 compression ratio... with all that known, a cam change and head change would do a world of change. As for what to change them to, well, everyone has their own idea of that. Ask around for a good cylinder head type(preferrably a 64 cc, maybe a 58cc chamber) and a good camshaft profile(old school designation would be about a 262 to 270 duration...get any higher and you could have vacuum issues at low rpm(ie headlights not wanting to raise easily :)
StingrayJim 
NCM Lifetime Member #1936
Stingray's '76���������������������������� StingrayJr's '78���������������������������Lil Red '94 
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Former Member
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New Albany, OH - USA
Joined: 8/17/2010
Posts: 173
Vette(s): 1980 Coupe /
Snowcrest White /
L48, 350 /
Comp Cam /
Edelbrock Heads /
Cyclone Intake /
Holley Carb /
Holley Fuel Pump /
Patriot Headers /
Dual Exhaust /
Magnaflow Mufflers /
1964 Coupe /
Riverside Red /
L76, 327, 365hp
I just went through an engine upgrade with my '80. I ended-up with the following modifications.
Comp Cam Hydraulic Roller Cam: Duration @ .050: 210 intake; 220 exhaust; Lobe Lift: .3340 intake; .3420 exhaust; Lobe Separation: 112-degrees; Gross Valve Lift: .501 intake; .513 exhaust.
Edelbrock E-Street Aluminum Cylinder Heads: 2.02-inch intake / 1.60-inch exhaust Valves; 64-cc Combustion Chambers; CR: 9.7:1 (measured).
Holley Street Avenger 770-cfm Carburetor.
Patriot Ceramic-Coated Tight-Tuck Exhaust Headers: 1 5/8-inch Primaries; 2 ½-inch Collectors.
Corvette Central 2 ½-inch Aluminum Dual Exhaust.
Magnaflow 2 ½-inch Mufflers.
Chevy 14 x 3-inch Chrome Performance Air Cleaner.
The car now runs significantly better than before. The mechanic I work with estimates that it is probably putting out about 350 - 370 hp. We plan on dyno-tunning the engine this spring to verify hp.
Chuck
Former Member
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New Albany, OH - USA
Joined: 8/17/2010
Posts: 173
Vette(s): 1980 Coupe /
Snowcrest White /
L48, 350 /
Comp Cam /
Edelbrock Heads /
Cyclone Intake /
Holley Carb /
Holley Fuel Pump /
Patriot Headers /
Dual Exhaust /
Magnaflow Mufflers /
1964 Coupe /
Riverside Red /
L76, 327, 365hp
I forgot to include the Cyclone Plus intake manifold.
Chuck
Lifetime MemberHOWELL, NJ - USA
Joined: 5/18/2004
Posts: 6812
Vette(s): 1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.
Chuck's combo is a good one. I had a 327 with Edelbrock heads, performer RPM manifold, Comp Cams 270H cam, headers, duals and a 2600 stall. That little 327 screamed!! 
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Lifetime MemberHOWELL, NJ - USA
Joined: 5/18/2004
Posts: 6812
Vette(s): 1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.
Heads. $1000
cam, lifters and pushrods. $150
intake $125
headers - $100 (cheapest)
carb - $275 - I'd go with an Edelbrock
gaskets, RTV, plugs etc - $75
timing chain $60 (always replace if you're swapping a cam unless it has low mileage on it)
water pump - same rule as above!! $50
edelbrock also sells kits with the heads, cam, lifters, intake and carb. I think they also include gaskets. May save you a few dollars.
Good luck!!
Paul
cam, lifters and pushrods. $150
intake $125
headers - $100 (cheapest)
carb - $275 - I'd go with an Edelbrock
gaskets, RTV, plugs etc - $75
timing chain $60 (always replace if you're swapping a cam unless it has low mileage on it)
water pump - same rule as above!! $50
edelbrock also sells kits with the heads, cam, lifters, intake and carb. I think they also include gaskets. May save you a few dollars.
Good luck!!
Paul
LukesVette Homepage
Veteran of Operation Iraqi Freedom
101st Airborne(AirAssault!)
God Bless America
Support Our Troops
Lifetime MemberHOWELL, NJ - USA
Joined: 5/18/2004
Posts: 6812
Vette(s): 1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.
LukesVette Homepage
Veteran of Operation Iraqi Freedom
101st Airborne(AirAssault!)
God Bless America
Support Our Troops
Former Member
Send PM
New Albany, OH - USA
Joined: 8/17/2010
Posts: 173
Vette(s): 1980 Coupe /
Snowcrest White /
L48, 350 /
Comp Cam /
Edelbrock Heads /
Cyclone Intake /
Holley Carb /
Holley Fuel Pump /
Patriot Headers /
Dual Exhaust /
Magnaflow Mufflers /
1964 Coupe /
Riverside Red /
L76, 327, 365hp
The cost of my upgrades was as follows.
Cam, etc: $1185, (Cam: $275; Lifters: $405; Springs: $74; Retainers: $21; Locks: $44; Timing Chain: $22; Wear Plate: $16; Roller Tip Rockers: $135; Long Slot Rockers: $73; Guidplates: $17; Studs: $19; Pushrods: $84).
Carb: $400.
Exhaust System: $630, (Headers, Exhaust, & Mufflers).
Aluminum Heads: $900.
Air Cleaner: $48.
Intake Manifold: $300.
Chuck
in Forum: C3 Engines
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