383 Upgrade... Cam/Exhaust/Porting/Intake/Carb with 1/4 Mile Times

[heal0048]

  This is for all those folks that have not built their monster stroker motor yet and want to see what they can do with their stock 383 until then.  I have a '67 Charger with a 383 that I have been doing some work on and I have some 1/4 mile results that I will share (not the fastest car... but still fun):

16-17 seconds - stock with Comp Cams Xtreme Energy 268 cam and restricted exhaust
 When I first bought the car the exhaust was so restricted from a hack job reducing the diameter to less than 1.25" in some bends that it was likely a 16-17 second car.

14.8 @ 94mph - 1 7/8 Hooker Comps with a 2.5" X-pipe and Flowmasters, 2400' density altitude
 I was running 14.8 seconds at 94mph with Hooker Comp headers and 2.5" mandrel with Flowmasters.  I also had 3.08 gears.  I was running a Comp Cams Xtreme Energy 268 cam (224/232 @ .050" and ~.480" lift).  Everything else was stock with a 4-barrel Carter 625.  2.20 second 60' times with the street tires.

14.45 @ 94mph - 4.10 gears, 2100' density altitude
 Next I went to 4.10 gears and was running 14.45 seconds @ 94.  2.10 second 60' times with the street tires.

14.25 @ 96 - Timing (same day as 4.10 gears), 2100' density altitude
 I then bumped the timing up from 35 to 38 and ran 14.25 @ 96.  2.08 second 60' times with the street tires.

13.5 @ 102 - cam, porting, rockers, intake, carb, 3500' density altitude
 The next upgrade started with a Hughes Whiplash cam (229/242 @ .050" and .552" lift).  The cam was degreed in straight up.  I really like the Whiplash cam with the sound and low-end torque improvement.  It pulls strong to about 5800-6000rpm.  The lobes are very aggressive and look similar to a roller cam (much more than the Comp Xtreme too).  The cam only pulls about 10" of vacuum at idle though - due to the lobe separation and it being built for low compression motors.  I upgraded the stock rocker arms to the Hughes 1.6:1 roller rockers... very nice pieces and the geometry was spot on with the roller dead center on the valve throughout the lift.  They also fit under the stock valve covers after removing the baffles.  I also did some mild porting on the 906 heads and used .020" head gaskets vs. the .040" that were on there.  The pistons are .080" below the deck so I figure I went from around 7.6:1 to around 8:1 on the compression ratio (still way low).  The stock intake was swapped out for an Edelbrock RPM (port matched).  I was able to fit the intake under the stock hood with an Edelbrock 5/8" drop base and I am still using a 3" air cleaner element.  It just clears the kickdown linkage.  The Carter carb was replaced with a Holley Ultra HP 750cfm.  I am now running 13.5 @ 102 (density altitude of 3500 that day) with 2.05 second 60' times (street tires and traction limited).  
 Corrected for sea level conditions I would run 13.1 now verse 14.0 for a 0.9 second improvement (from the last bunch of upgrades).  I am still running 38 degrees total on the timing and next time I will see if 40 degrees is an improvement or not.  

 Next for me is Caltracs, slicks and maybe a smaller, higher stall converter.  

Engine: 383

Pistons: Stock/flat .080" below the deck

Compression Ratio: ~8:1 with .020" head gasket

Heads:  906 with mild porting and polishing

Valve sizes and Flow numbers if available: 2.08/1.74, unknown flow

Cam: Hughes Whiplash flat hyd, 229/242 @ .050 and .552" lift

Valve train: Hughes 1.6 Roller Rockers

Exhaust: Hooker Comp Ceramic Headers with 2.5" mandrel x-pipe and flowmasters

Intake: Edelbrock RPM

Carb: Holley 750 Ultra HP

Trans: 727 with Transgo -2 kit

Torque converter stall (if auto): ~2600 (probably 12")

Gear Ratio: 4.10:1

Tire type/size: Dried and worn out street tires (27x8x15)

Elevation: 1100

Hp/torque: ~400/420 (optimistic at the crank)

Et/mph: 13.5/102 (sea level 13.1/103)

Additional comments: Hughes Whiplash cam pulls about 10" vacuum at idle... not enough for the power brakes.  I tried a reserve canister and did not help much.  I had to go with the electric vacuum pump and it works great.

[BSB67]

Nice post.   

As you are continuing to work on the car, be sure to collect detailed atmospheric data for each run with an inexpensive weather station.  When you get home you can correct all of the data so your results will be apples to apples.  This will really help you determine the benefits of each change.  As an example, the 14.45/94 to 14.25/96 could be all timing, all atmospheric, or a combo of both.

Be very consistant on the shift point.  Usually the 383/tight converter/heavy car's et&mph is sensitive to the 1-2 shift recovery, and usually ets better shifting out of 1st at a higher rpm.

Finally, be carefull to not confuse a a better et with a hp improvement if your 60 is not consistant.  If you have a 0.05 sec. improvement in 60, the et will probably be lower (better) by 0.10 sec.   I presume that you have the power and gear to easily spin the tires at the launch, therefore if you 60 is better, its probably due to driving technique.

Keep it up, and keep posting.  Good luck.

[heal0048]

Good words and thanks for the advice BSB67!  I will be sure to track the weather a little better.  I modified my post to clear up any questions on the density altitude... the 2 tenths gained from the timing was actually the same night at the track (2 runs at ~14.45/94 with 35 degrees and 2 runs at ~14.25/96 with 38 degrees)

Previous to my most recent upgrade, traction was not an issue at the track with the vacuum secondaries (but right at the edge of spinning).  Now it is a issue with street tires and the 60' times are almost the same due to traction as the limiting factor - although much more low-end torque is available now.  Now that I have some more hp (trap speeds went from 94 to 96 to 102), I will work on the efficiency again, i.e. traction and converter.  I understand your comment (BSB67) about the 60' times, E.T. and hp... of course, no power gained with the 4.10 gears; however, .12 better 60' times and about .3 better E.T. 

[BSB67]

My car will pick up a tenth on some evenings from the time T&T starts in early evening to the last couple of passes due to changing atmospheric conditions, FWIW.

[lasvegas69charg]

I was thinking about the eldelbrock top end kit which includes heads, cam, intake. Has anyone have any experience using this on a stock bottom 383?

[Budnicks]

I was thinking about the eldelbrock top end kit which includes heads, cam, intake. Has anyone have any experience using this on a stock bottom 383?

Kind of old thread, sorry didn't see it until after I posted this response, it's still relevant thou... I'm sure some here will disagree but, the Edelbrock 84cc RPM Alum. heads & Intake are a good idea, just the near 100# weight savings alone, {w-larger valves & hard seats} between the cast iron heads & intake weights, will make a difference in performance & handling, the out of the box flow characteristics of the RPM's are far better then the stock cast iron 906 heads, it can bump the compression up slightly too, for the aluminum heads, but IMHFO I would go with another/better camshaft, than the one Edelbrock offers, some quality adjustable rockers, good hardware/bolts &/or studs, with proper length/style of push-rods {camshaft base circle & head gasket thickness, will determine that usually, but always check them no matter what}, better lifters & a properly sized carb, for your intended usage, with a 700-750-770cfm Holley HP or Quickfuel or Proform dual feed carb w-electric choke if it's going to be street driven in colder weather, DBL Pumper if it's a stick car too, add some 1-7/8 TTI 383178 headers, mandrel tubing w-2.5"-3" exhaust & an X or H-pipe, better fuel pump & larger size sending unit & fuel lines, w-hotter ignition, coil & low ohm resistance wires, free flowing K&N or gauze type air filter, you'll be happier IMHO... you can get about 75-100-125 more HP pretty easily, depending on what mods & parts you choose, it ain't cheap thou, but well worth the money spent, if you want that sort of thing, not of the purist mentality... you can get about 2.06hp per/cfm of flow, I would still check the heads, before installing them, no matter who's heads you choose to use... good luck

[Ryan.C]

I was thinking about the eldelbrock top end kit which includes heads, cam, intake. Has anyone have any experience using this on a stock bottom 383?

Kind of old thread, sorry didn't see it until after I posted this response, it's still relevant thou... I'm sure some here will disagree but, the Edelbrock 84cc RPM Alum. heads & Intake are a good idea, just the near 100# weight savings alone, {w-larger valves & hard seats} between the cast iron heads & intake weights, will make a difference in performance & handling, the out of the box flow characteristics of the RPM's are far better then the stock cast iron 906 heads, it can bump the compression up slightly too, for the aluminum heads, but IMHFO I would go with another/better camshaft, than the one Edelbrock offers, some quality adjustable rockers, good hardware/bolts &/or studs, with proper length/style of push-rods {camshaft base circle & head gasket thickness, will determine that usually, but always check them no matter what}, better lifters & a properly sized carb, for your intended usage, with a 700-750-770cfm Holley HP or Quickfuel or Proform dual feed carb w-electric choke if it's going to be street driven in colder weather, DBL Pumper if it's a stick car too, add some 1-7/8 TTI 383178 headers, mandrel tubing w-2.5"-3" exhaust & an X or H-pipe, better fuel pump & larger size sending unit & fuel lines, w-hotter ignition, coil & low ohm resistance wires, free flowing K&N or gauze type air filter, you'll be happier IMHO... you can get about 75-100-125 more HP pretty easily, depending on what mods & parts you choose, it ain't cheap thou, but well worth the money spent, if you want that sort of thing, not of the purist mentality... you can get about 2.06hp per/cfm of flow, I would still check the heads, before installing them, no matter who's heads you choose to use... good luck

I will be going down this road with my stock bottom end 383 in a few months. What are some good cam & Intake manifold choices for a 4 speed car w/3:55's out back. My car is primarily a street car.

[Budnicks]

I was thinking about the eldelbrock top end kit which includes heads, cam, intake. Has anyone have any experience using this on a stock bottom 383?

Kind of old thread, sorry didn't see it until after I posted this response, it's still relevant thou... I'm sure some here will disagree but, the Edelbrock 84cc RPM Alum. heads & Intake are a good idea, just the near 100# weight savings alone, {w-larger valves & hard seats} between the cast iron heads & intake weights, will make a difference in performance & handling, the out of the box flow characteristics of the RPM's are far better then the stock cast iron 906 heads, it can bump the compression up slightly too, for the aluminum heads, but IMHFO I would go with another/better camshaft, than the one Edelbrock offers, some quality adjustable rockers, good hardware/bolts &/or studs, with proper length/style of push-rods {camshaft base circle & head gasket thickness, will determine that usually, but always check them no matter what}, better lifters & a properly sized carb, for your intended usage, with a 700-750-770cfm Holley HP or Quickfuel or Proform dual feed carb w-electric choke if it's going to be street driven in colder weather, DBL Pumper if it's a stick car too, add some 1-7/8 TTI 383178 headers, mandrel tubing w-2.5"-3" exhaust & an X or H-pipe, better fuel pump & larger size sending unit & fuel lines, w-hotter ignition, coil & low ohm resistance wires, free flowing K&N or gauze type air filter, you'll be happier IMHO... you can get about 75-100-125 more HP pretty easily, depending on what mods & parts you choose, it ain't cheap thou, but well worth the money spent, if you want that sort of thing, not of the purist mentality... you can get about 2.06hp per/cfm of flow, I would still check the heads, before installing them, no matter who's heads you choose to use... good luck

I will be going down this road with my stock bottom end 383 in a few months. What are some good cam & Intake manifold choices for a 4 speed car w/3:55's out back. My car is primarily a street car.

I'm not really trying to be too vague, but I would suggest you call a reputable camshaft mfgr & tell them what your exact combo is & tell them honestly what you expect to achieve, what parts you already have & plan to use, what your performance expectation honestly actually are, stuff like your, rocker ratios & style of rockers, cars weight, type & size exhaust, what gear ratios & tire size /type, {converter if it was an auto} clutch type for manual, carb/intake, fuel system, compression & bore size {how far down in the hole the pistons are & what size valve reliefs if any}, head gaskets thicknesses, combustion chamber sizes, ignition system etc.... I don't really like giving cam recommendations, it's way to subjective, what my budget & build style & what I will tolerate or what I like, may not be what fits your wants/needs, I like & usually use roller cams Hydr. or Solid, over flat tappet cams, also adjustable rockers over stock stamped steel types, like most the guys here probably would recommend.... I would recommend the Edelbrock RPM dual plane manifold for street use {with a Holley type Carb/not Edelbrock} with the Edelbrock RPM heads, heads & camshaft will make the biggest differences in a BB wedge power, I never scrimp in that area of a build... good luck, sorry I couldn't help more, I leave that stuff to Camshaft mfgr experts, that's why they are in the business... I personally like allot more gross valve lift, with less duration, than many people here, will probably recommend thou, it's always worked well for me...

[Ryan.C]

Thanks, I will be making some phone calls then.

[Cooter]

Yes, Well worth the time IMO as today's cam profiles are awesome. Just did a 700 HP Small Block Chevy for a customer and he called for a Rec. On the cam.
I "Guessed" at which one he would be ok with. Turns out I was a little "off" to say the least. Turned out great. I have little Experience with Boosted engines, but am learning bout Cams for them.