stevenb

With the specs listed below, I'm not sure if I have achieved all the horsepower my engine should produce. Now my friend has a stock 89 foxbody gt mustang and isnt even sure if my car is faster! Is there anything that can prevent me from achieving what my engine should/could? Now my car is a stick and im decent at driving, not very smooth but what else could it be or am i overrexagerating? I mean I know its quick but related to a 302 mustang with 235 stock horsepower?( I think?)

OH, also my engine hasn't seen 300 miles yet. Just breakin her in.

Guest

What is it you think you should have?

I'm not sure what your cam is, but I'll bet a bunch of people are going to recommend ditching that carb. Those heads are... ok, but there's more to be had. Are they ported?

AlkyIROC

Using programs like Dyno/Drag 2000 assumes everything is 100% perfect. There are so many little things that can affect the performance of a vehicle.

Ignition timing and timing curve
Fuel jetting or any other fuel related issue, float setting, pressure, octane etc
Valve lash if using a solid cam
Spark plug gap and plug temperature
Tire pressures
Suspension geometry, weight transfer, gearing
Vehicle weight

There are cars with lots of power but don't run what they should and there are other cars like in Stock Eliminator that run extremely fast with low HP numbers.

84 z28

Get rid of that carb and step up a bigger size and go with a double pumper.

sofakingdom

iTrader: (1)

A mismatched combo.

Like:

A 244° @ .050" cam from the Stone Age (If I'm guessing right.... ) sort of similar to this one maybe http://store.summitracing.com/partde...art=SUM%2D1108 (stop me if I'm wrong) that needs about 11½:1 compression to even begin to work right, with aluminum heads

Compression somewhere in the mid 9s (assuming your 350 has typical "rebuilder" flat tops, like TRWs or the like); about 2 points too low for the cam

An intake manifold that's basically stock, guarantees that the whole system will not be able to flow enough air to ever reach high enough RPMs that the cam would work to its optimum potential

A carb that runs out of flow before the (over-cammed) engine even reaches the bottom of its torque band

Posibly, poor gearing, that keps the engine in a low RPM range for so long that by the time the car builds up enough speed for the (over-cammed) motor to begin to produce any power at all, the car in the other lane is long gone

Other than that, exhaust; and TUNING.

Oh, and maybe, poor camshaft selection.

Those are a few typical things that make a motor not live up to expectations.

stevenb

So your saying that I need to upgrade to a bigger carb, get a better intake manifold, and are you saying I need to get a smaller cam, or get better heads? What do you mean by saying my cam may be from the stone age? Any suggestions I should do on changing some parts to get the correct combo and should I get a dyno to see what numbers I am actually pushing?

My compression ratio is approx 9.7:1 and that cam you suggested is close, but not exact yes.

Also, I know you guys are saying my engine isn't combo'd right, but is it actually HURTING my engine or just not lettin her go as much as she should?

84 z28

I have a 355 with a cam that has 515 lift, dart s/s heads that have been massaged a little bit and 650 mighty demon carb. its runs very well. Im guessing low 13's high 12's when I finally get it dialed in.

Sonix

iTrader: (1)

The straight pattern version of the .510 lift cam? 244/244?

You should get a better cam, not necessarily smaller. Those heads are 200cc right? He's saying you need 11.5:1 if aluminum, to run that big cam. Or 11:1 iron or so.

What are your measurements to get 9.7:1 CR? Was the block decked?

You could either upgrade the carb and intake, or downgrade the heads and cam. Make them match, that's key.

F-BIRD'88

be more specific about exactly what is in the motor.
What .510" lift cam? the gear drive is costing you around 25 to 40hp. (friction)

Even if the cam is from the stone age if it is installed right and combined with the right parts it will run hard. You can probabily correct the compression ratio with a head gasket change.
Most ".510" lift cams are in the 246-246 or 244-254 range duration. which is yours? name brand pn grind#

The performer manifold and 600carb are costing you 35hp .
You make no mention of the exhaust .
Your car is likey way under geared. Needs a 4.10 gear minimum.

The Sportsman heads need porting to realize their potential. mostly in the bowl area around the big thick as cast valve guide bosses.

I would change to a 4.10 or 4.56 gear, use a thin steel shim gasket to get the cr up. Go with a Vic JR and 750cfm DP carb 1-5/8" or 1-3/4" long tube headers.
I would move the cam in the motor to a 102-104 intake C/L
There are other cams. I know of a few specificly that work great with sportsman II heads but yours may be usable. need details.

You need a big free flowing exhaust system to make power.
you can easily run high 11's to low 12's with a simple 350 using sportsman heads. but it requires detail and
the right parts and some hand preparation of the heads and intake manifold.

sofakingdom

iTrader: (1)

Or, since you have 64cc heads and no realistic way to get up to enough compression to use a cam like that one, get a more appropriate cam; and go from there.

I'd suggest something in the mid - high 220s @ .050" on the intake; and probably about the same on the exhaust. A narrow lobe sep angle like about 106 or 108°, would be much better than the way they usually grind those old ones (114°, alot of the time). No more intake duration than about 230°, unless you have AT LEAST 3.73 gears.

A larger intake and carb would help too; mostly the intake.

I'm guessing here, that the way the car runs now, is it doesn't have ANY leave; starts to come on pretty good to whatever extent it does (press you back in your seat) at maybe 4200-4500; then it rapidly falls off and is TOTALLY done (less pressure into the seat) by 5500 or so. Am I very far off?

Do you have your latest dyno run graph or numbers?

stevenb

My cam is from a brand called Engine Pro, one that until now I have never heard of. My range duration is 244. My exhaust is hooker short pro comp headers with little turbo mufflers, dual exhaust dump before axle.

No, the block was not decked. I had people look at it on here and I had a guy who does heads daily do my valve job and said with my flat tops with valve reliefs I had around 9.5:1 with those and the 62cc or 64cc sportsman 2 heads. Yes they have the 200cc intake runners. Butttt, to be quite honest I'm not sure which it is 62 or 64cc.

My LSA is 107/109. I have not done a dyno run or numbers yet. I dont feel like it loses kick at all from 5500 RPMs to redline or so. It seems like its pretty much the same maybe even a better kick to the seat after higher RPM's. What kind of intake manifold can you recommend? I was thinking of getting a 4.11 gear anyways eventually, would that help a lot?

F-BIRD'88

With a cam having 244 deg duration @.050" "107/109" LSA in other words 108LSA advanced 1 deg and .510"-.510" lift your best power band is 3500 to 6500rpm. This cam likes a good bit of compression ratio and either a performer RPM style or Vic JR style manifold and a 750cfm carb. The performer manifold and smallish 600cfm carb is costing you power. Long tube headers would be better than the shorties. The short headers can be improved with collector extensions and possibly a Y collector to join the headers into one big 3.5" main exhaust pipe to increase torque. See flowmaster #Y250350. If your exhaust pipes are smaller than 2.5" you definatly need to work on the exhaust.
Because your compression ratio is modest you can, and most likley should advance the cam in the motor to maximize cylinder pressure and best average torque output.
Move the cam installed position so that the intake valve closes at 44 deg BTDC @.050" lifter rise (102 intake C/L) You'll be advancing the cam about 5 degrees in the motor.
Consider swappin the head gaskets for a thin .015" gasket and or milling the heads to raise the cr.

I would lock out the distributor mechanical advance and run full advance 34-36deg BTDC all the time. Vacuum advance will need to be limited to about 12-15deg. this will increase the bottom end torque and throttle response a lot and make it idle a lot nicer.

The heads need to be ported. The ports are plenty big bet the shape especially around the valve guide bosses needs work. the intake manifold reguardless of which one you run needs to be port matched to the big ports on sportsman heads.
You definatly need more rear gear ratio. 4.10 minimum.
While your in there degreeing the cam timing and advancing it, ditch the goofy gear drive for a timing chain and gear set and make more power.
Easy solid 12 sec performer with these tuning changes. Its just a matter of dialing it all in.

stevenb

Yes, right now I have 2.5" exhaust...I'm going to be honest just getting the shorty headers on was a pain. I barely got em on. And now that I got a summit torque starter, I think itd be harder. Any techniques or anything special how to get em on? Also, I know I am not giving my engine the power it can handle or what it is designed for, but am i hurting it really? Does allowing your engine to not receive what it should cause too much stress or anything?

http://store.summitracing.com/partde...5&autoview=sku

An intake manifold just like this one? How do you port match them?

How long will by 3.42 approx last on this engine?

I feel stupid for not mentioning this....it is a street car with the occasional take to the track someday car.

F-BIRD'88

I remove the engine to install headers on these cars. A lot less swearing and cussing. A car engine is a machine not a human being. i does not feel stress, or toomuch stress. But can be over stressed mechanically by too much rpm, lean air fuel ratios or lack of lubricant or cooling.
Your 3.42's will last just long enough for you to get some 4.10's.
Buy this book http://www.amazon.com/Build-Performa...2590168&sr=8-1 head porting intake manifold porting and much more is covered. There will be a test

Sonix

iTrader: (1)

I prefer to install the headers when the car is in. My hedmans fought me when I tried to install the engine with headers on. PS frame and steering shaft mostly....
That book is pretty good though, it's great reading.

19doug90

long tubes can be done, passenger side is easy if they dont hit the k-member. drivers side had to jack the motor up to the firewall with the dist cap off, and there was just barely enough room to rotate them in (i have a lakewood scattershiled that gets in the way of EVERYTHING) but there was only 1 way they would go and it *wasnt* straight up and then rotate them in like most people suggest