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Finished rebuilding my engine and performed dyno test. In my four runs, power was consistent and peaked at 246 hp and 333 ft-lbs at the rear wheels. I was hoping for more. Below are the specification of the rebuild. This was my first attempt to rebuild an engine. Request input to unleash the rest of the potential in this engine! Should I just change the Carb or bolt on a Blower?
Block: SBC 400, 2 bolt main, bored 30 over to total displacement of 406. Casting number: 3951509
Rods: Stock
Crank: Ground and polished 0.010”
All bearings replaced with Sealed Power bearings; cam, main, rod
Pistons: Dish, with four valve reliefs, Hypereutectic aluminum, +12.50 cc/piston. SLP-H601P30
Edelbrock Top End Kit 2022. EDL-2022
a. Cam: Hydraulic Flat Tappet, Advertised Duration 278/288, Lift .420/.442
b. Heads: E-Street, Aluminum, 64cc Chamber, 185cc Intake Runner, 60cc Exhaust Runner, 2.020in Intake Valve, 1.600in Exhaust Valve
c. Intake: Performer EPS, Dual Plane, Aluminum, Square Bore
d. Timing Chain and Gear Set, Performer-Link, Double Roller, Iron/Steel Sprockets
Rocker Arms: Proform Parts, Stud Mount, Full Roller, Aluminum, 1.5 Ratio. PRO-66914
Push Rods: Edelbrock Hardened Steel, Heat-Treated, 5/16 in. Diameter, 7.900 in. EDL-9629
Carb: Edelbrock Performer, 600 cfm, square-flange, electric choke.
Hedder: Hedman Hedders, Street, Full-Length, Steel. HED-68310
Exhaust: Dual, no cat, free flow mufflers.
Distributor: Pro-Billet Ready-to-Run, Magnetic Pickup, Vacuum Advance. MSD-8360
Coil: Blaster 2 Coil. MSD-8202
Plug Wires: Super Conductor, Spiral Core, 8.5mm, Red, 90 Degree Boots. MSD-31359
External Damper: Harmonic Balancer, SFI, External Balance. SUM-C4266
Flexplate: 168-Tooth, External Engine Balance, 2-Piece Rear Main Seal, SFI 29.1. SUM-G101SFI
Fuel Pump: Stock 1984 305ci pump.
Water pump: Mechanical, Long, High-Volume. SUM-311006
New alternator, stock A/C unit installed.
Transmission: Bowtie Overdrives 200 4R level 2, 2200 rpm Heavy Duty torque converter.
Rear Differential: GM 7.5” 3.08 open.

 

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What compression ratio did you end up with? Was the cam timing set?
 

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Put on a Holley,that may help for what you have a 600 is not enough, not sure why you went with dish pistons,with the pistons and head combo you have youu are loosing compression,a few CC makes a big difference on compression . to get the power out of the set up you have,you may need to add a blower or SC, i would sure try more cfm on the carb first . the Hp and Torq, seams way off for that set up .:dontknow: also i looked at the specks for the cam,thats not much over a stock cam,your not going to get much HP out of it ..
 

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When you say bolt on a blower you will ultimately have to change out your carb anyway to a blow through type. You have a relatively mild camshaft for the rest of the components in your engine. Actual duration on your cam is only about 218-220 degrees. You need more lift also. A suitable hydraulic flat tappet cam would be around .480 lift and 230 degrees at .050. You can also install 1.65 ratio rockers to increase your valve lift.
 

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Without knowing the rpm at which torque peaked, it looks like you've build a pretty good engine for a daily driver. I'll bet it drives very well.

However, I agree that if horsepower is your goal, the cam is small for the displacement and you may want to go up about 10 to 15 degrees on both the intake and exhaust side. You also have headers, which can hurt the bottom end numbers, so unless horsepower peaks in a range where the headers are most beneficial (over 4000 rpm) they can lower your numbers as well. I would not be too concerned about the 600 carb unless you are running over 5000 rpm.

If you do not have an O-2 sensor in the exhaust so the dyno folks can read the air fuel ratio, you need to add one. Being overly rich hurts power and being lean hurts engines, so that is the first change I'd make in trying to find more power.
 

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Discussion Starter #6
Thanks for the advice. It appears that a consensus is replacing the Cam. I just looked up 2 different models.
Edelbrock 5002: Int 232/Exh 234, Lift Int 0.488/Exh 0.488 or
Edelbrock 2201: hydraulic roller, Int 234/Exh 238, Lift Int 0.539/Exh 0.548
Both appear to offer more power and still be able to drive daily. Any thoughts?
 

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I would check piston to valve clearance on any cam with lift over .500". Both cams will give you a noticeable increase in power.
 

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if it was me, I'd go with a cam with duration around 268 and 456 lift. This would work real well with the rest of your system, and still get decent mileage. would give you real nice torque numbers and "seat of the pants " feel from around 2200-4500 rpm. those are real world usable numbers, not bench racing numbers.

:nanawrench:
 

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with the 12 cc dish and 64 cc heads it is near 10 to 1. a flat top 400 is around 12 to 1 with small heads . the carb is way too small and the cam is small for a 350 and way too small for a 406.you didnt do your dyno in od i hope.that combo should be good for about 320 hp.try a bigger carb,750/800 is more what they like.also try some 1.6 rockers to make the cam bigger.i ran a 500 hp 406 for years.you built yours very close to original stock and they were about 210 hp
 

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You motor has like 10.5:1 compression. That thing should be makin about 400hp. I think your leaving a lot on the table with your camshaft and when you do put a cam in it its going to need a bigger carb because 600cfm on a 406 is good to about 5100rpm and you'll be spinning it 6000+ (Get a Holley double pumper).

The hypereutectic pistons were not the best choice for making power and saving weight, but this is your first engine and this is how you learn. Are the crank and rods cast iron or forged?

I wouldnt do more than a cam and a carb to this engine. Because of the pistons, adding boost is out of the question. You could just leave it alone too, I bet it has a ton of torque!!

Good job on your build!! :goodjob:
 

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all stock 400 cranks are cast and all small block rods are forged.you have very nice parts for a 350 but way small for a 400. the heads are small ,i ran the dart sportsman 2 heads 200cc 64 cc. a 280 duration cam will idle smooth in a 400 and lope in a 350. look for something in the 290 duration and 480/490 lift. if you need a smother idle get a cam with a wider lobe seperation angle 112/114. if you can have a rumpy idle go tighter 106/108. try the performer rpm intake they make great power.you need to remember a engine is a big air pump,the easier you make it to move air through it the more power it will make.restrictive cam,carbs,heads all take away power.the heads you have are designed for a 350 and you are stuffing 50 more cubes through them.so cam ,rockers and carb/exhaust need to be optimized to get the most you can out of it
 

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no dout you have more potential there but if it was me,
for a daily driver,,i'd throw some 3.73 gears and a posi behind that 2004r..
if its a weekend driver maybe some 4.11s,, its still not bad unless you do a bunch of freeway drivin..
if your plannin on gears any way?? they would really wake it up out of the hole,,
try it and if thats not enough?? then go back in the motor.. but thats me..
what are your plans?? daily,, weekend,, drag racin?? :texas: oh yea..WELCOME
 

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Discussion Starter #15
Well parts have been ordered for more power.
EDELBROCK PERFORMER SERIES 750 CFM, PN#1411
and
PERFORMER RPM CAMSHAFT 234/244 at 0.50 and 488"/.510", PN#7102
This weekend, swap out parts and next week reperform dyno test!

To answer another question, this is my daily driver. Ideally my next major improvement will be replacing the current 7.5" open differential with a Currie 9" Rear end, built with 31 spline axel, and 3.70 final drive. Saving up the 3k required.
 

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also check retainer to guide/seal clearance on your heads above .500 lift.most heads are good out of the box to .500 lift. if they hit it makes short work of the seals and cam lobes. you want atleast .100 thou clearance from the bottom of the retainer to the top of the valve seal at max lift and as stated above check spring compatability with the new cam. good luck:beer:
 

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Discussion Starter #18
Delay in plans, Called Edelbrock Tech rep today and I have to get different Valve springs to support the more aggressive cam. Ordered ISKY 295-D, going to take about a week and a half to make it out to Hawaii. Recommended by Edelbrock for the cam. Replacing this cam shaft is turning into a much more involved project. Any trick to replace the valve springs and keeping the heads installed? Worried about dropping a valve into the cylinder.
 

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you can fill the cyl with air to hold the valves closed if you have a compressor or you can fill the cyl with rope and turn the piston up by hand and it will keep them in place. not personally done the second but have heard of others here doing such
 

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Well parts have been ordered for more power.
EDELBROCK PERFORMER SERIES 750 CFM, PN#1411
and
PERFORMER RPM CAMSHAFT 234/244 at 0.50 and 488"/.510", PN#7102
This weekend, swap out parts and next week reperform dyno test!

To answer another question, this is my daily driver. Ideally my next major improvement will be replacing the current 7.5" open differential with a Currie 9" Rear end, built with 31 spline axel, and 3.70 final drive. Saving up the 3k required.
Awesome!! :rockon:
 
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