50thZ

I have already searched the web and this forum, but not having any luck with finding what cam most people are running in a 1973, auto, l48 car. My $h1t box is week on the power side and need carb rebuild. Pulling it apart Thursday and planning on a cam swap. If it was and LS motor like my 03 Z I would know exactly what to go with. However, this old carb car is new to me. Worried about PTV clearance....any help would be gratefull.

marc1973

I'm not a cam expert but I have 1973 l48 I rebuilt with flat tops because after I had the heads off I didn't have enough compression to utilize the heads I wanted,

If you plan on only changing the cam you basically going to be left with nothing but rv and 4x4 cams or else your dynamic compression will go under 8 really quick, if you haven't done anything I'd try putting long tube headers on and recurving the distributor before diving into switching cams

50thZ

I don't mind a stump puller. Light to light. Not going to run the quarter ever. Never see over 70. I bought it for my wife. When I drive it however it irritates me with is snail like movement.

marc1973

I'm not sure cam wise what would be good for stock, emailing cam manufactures for recomendations will get you in the ballpark of what you want,

Also I'd try recurving the distributor before anything else when my l48 was stock it made a world of a difference when I advanced the timing

Good luck finding the right cam I'm sure someone more knowledgeable will chime in soon

lowes-yellow77

I have found through this forum if its a Quadrajet and timing help, contact Lars he sent me a email I can dig it up of you dont get ahold of him.
The car should have duals being a 73 and no catalytic converters. A cam might help here is sime specs I had saved from sometime ago

Here's the specs from the GM site:

12353917 Camshaft Kit
8.0 - 9.5 to compression ratio, 2200 - 2600 cruise rpm. Basic rpm range 1500 - 4000, 6500 rpm attainable with proper valve springs and lifters. All model small-block Chevrolet V8 1955-66 California, 1955-68 with federal emissions. All non-emission trucks, and 1966-92 for off-highway applications.

Technical Notes: These are hydraulic flat tappet camshaft kits. The duration at .050 lift (intake/exhaust) is 204/214 degrees, and the valve lift is .420"/.442". Lobe centerline is 112. This camshaft kit is designed and manufactured by Crane Cam Co.&reg. It contains one camshaft and 16 tappets

Here's the specs for the "929" cam that was used in the base engines includine 300 horse 350s. You can see that the 917 is a better deal and I think you will like it.

12364051 Camshaft kit, Hydraulic
Dual pattern, blueprinted replacement for factory P/N 3896929 with 300 hp and 327 cu. in. camshaft.

Technical Notes: Basic rpm range is 1000 - 3500; cruise rpm at 60 mph is 1600 - 2200 and compression ratio is 7.75 - 8.75. The duration at .050 lift (intake/exhaust) is 195/202 degrees, and the valve lift is .390"/.410". Lobe centerline is 112. This camshaft kit is designed and manufactured by Crane Cam Co.&reg. It contains one camshaft and 16 tappets

I think any of these cams will work No problem with power brakes or Stock converters.

Right now I have a 75 block 60 over small dish pistons and 67 291 heads and I use a 286H .480 lift and it runs very well, but I have headers, gears, Ignition upgrades, intake, 4 speed.

If there are a substantial amount of miles of the engine sometimes even putting a new cam will help bring life back to it.

-Lowe

mikem350

If its got hi miles new timing gears and chain helps. As said a good advance kit in the dizzy really helps a smog motor along with LOTS of initial advance. Also 1.6 rockers

cardo0

Have u tried a search for the L48 here? The L48 gets new heads and cam here every week. More posted in threads than i could ever say. If u have any specific questions there many here anxious to help.

Shark Racer

The 12364051 cam mentioned is basically the stock L-48 cam.

Headers, carb rebuild and ignition timing are the biggest improvements you can do to a stock vette.

The .420/.442 cam will work pretty well in a stock engine. Much beyond that and you may as well go whole hog... heads, cam, intake. Sky's the limit there, so most people will start factoring against a budget. Vortec heads and that cam would get you a great boost for the dollar, but if you want to go past that you should start looking at the name brand aluminum heads.

Hope that helps.

TedH

VERY warmed over L48 (see sig).

wilcar

I have used 2 diiferent Isky cams in 2 low compression mild performance upgrades. I used an Isky 262 super cam 208-208 @ 050 .440 lift 108 lsa in a 305 el camino with a 2 barrel carb and stock valve train. Definate improved low and mid range power. For my 76 L82 with auto trans I used the Isky 264 mega cam 214-214 @ 050 .450 lift 108 lsa and this cam had much better low end than the L82 had. I had the stock exhaust manifolds with single cats in both cars and both cams passed emissions in the 1990s.

63mako

http://www.summitracing.com/parts/cc...make/chevrolet

As others have said, distributor recurve, dial in the carb and make sure tune is optimized. Next would be headers and true dual exhaust. Biggest issue is compression, or a lack of it. You will be at the point you could pull the heads by just removing the bolts. New heads will help big time. Trick flow has a 56CC chamber
http://www.summitracing.com/parts/tf...make/chevrolet
that, when combined with a felpro 1094 head gasket changes your compression from under 8 to 1 to 9.7 to 1 with way better flow. Power is made in the heads and proper cylinder pressure. Cam only determines what RPM range power is made at or what RPM range the engine has proper cylinder pressure to make peak power. Increasing compression and flow (heads) increases cylinder pressure and the right cam can take advantage of that. Changing only the cam will get you a little but not as much as you would think.

TedH

The very first improvements I made to my '80 L48 from '97-99:

With 1999 Rebuild:
K&N filter in reconditioned OEM cold air induction system (all thermal actuators disabled/fixed wide open)
Recurved a fresh Accel Perf Replacement HEI distributor for performance.
Adjusted initial timing to compliment
Lars-rebuilt q-jet (re-jetted, repaired and fixed a lot of ills)
Hedman Hedders, 2.5" True duals and dynomax super turbos
Edelbrock Performer intake (3701)
all-new vacuum hoses/systems (resolved many leaks that caused erratic performance)
fresh set of 882 heads (2.05/1.60) 165cc intake runner
Crane Energizer 272H10 cam (a really good torque cam that really livened my engine up)
Hypereutectic pistons H345NP, block bored .020" over

Around 2002:
DART Iron Eagle heads (see sig)
Bow-Tie Stage-2 700R4 trans with 1800-2000 stall (close to stock)
3.54 gears in a fresh Dana 44 assembly
Van-Steel rear bearing assemblies/t-arms/half-shafts
Shortened and balanced drive shaft
Taylor Spiro Pro 8mm wires
2.5" h-pipe added to exhaust system

2013:
Retro roller cam conversion (see sig)
freshened DART heads
Edelbrock Performer intake (2101)

Next:
A fresh short block with just a tad more compression

Shark Racer

Ted - did you mean 2.05 or 2.02 valves on the intake side? It was my understanding that there isn't a ton of room on the 882s for big valves... some have issues w/ just 2.02s.

hotrodnick

The first time my mechanic drove my car he wanted to work on the power. He rejetted the carb, a Pertronix distributor upgrade kit (adjustable curve and advance) from Summit, changed springs to allow 4 barrel to come in sooner. I have a K&N filter and the cat was gone when I got the car. If grab second just right I can chirp the tires

TedH

The auto parts store that sold the 882's claimed the heads had all-new parts and 2.05" valves. I took them at their word. It was back when Advance was still Western Auto and I bought the pair of heads to replace my tired 624's.

Normally, the 882's have either 1.94 or 2.02" intake valves.

The 882's now occupy the cardboard boxes that my DART heads (2.02" intake valves but 180cc intake runners) came in.

Shark Racer

If you ever get bored and feel like checking, I'd be curious... just cuz I'd never heard of that before. Pics of the combustion chamber would be neat too.

Nothing's impossible, though!