singerso

Hey Guys, wonder if anyone can point in the right direction. I have a freshly overhauled 289(approx. 500 miles on it) with a new C4 and 3:20 rear. The block is a 289 hipo, .030 over, Crank .020 under, new Hypereutectic Pistons, new Edelbrock Performer-plus Cam, Double Roller chain, Performer Intake, 600CMF Perform Carb (elec. choke), rebuilt stock heads with Edelbrock match springs, Pertronix Flame Thrower HEI Distributor, Patriot tri-y headers and full 2.5" Flowmaster exhaust. The overhaul was performed with meticulous attention to detail and all specs were literally triple checked.

She runs and sounds great, but theissue I'm having is a lack of noticeable horsepower. At Edelbrocks request, I've stepped up the springs and metering rod and believe it's dialed in as good as it's gonna get. The Timing is set to 40 degrees total advance and the lash appears to be set correctly. Now, I've driven a friend’sridewith a similar but more mild (stock with 4bbl) 289 setup and the difference is obvious. Several other experienced friends have driven her and say the same thing....

I value the feedback from this forum and wonder if my expectation are simply too high or I should looking somewhere for specific to recover what appears to be a loss of HP. I'm already considering upgrading the Cam to an RPM or more aggressive CompCam and will eventually replace the heads with an alum setup. In the mean time though, I feel like I should be getting so much more out of this, thus what do you guys think?

Gun Jam

did you drive it before the rebuild or is this the first time driving it?

Is it shifting into 1st or are you accelerating in 2nd or 3rd from a dead stop?

That engine, trans, and rearend is close to what I had...You should get about a 0-60mph in 6 sec or less...Time it with a stopwatch (if your speedometer has been matched to the gears)

-Gun

singerso

Hey gun, I had a feeling you'd be one of the first to respond...She shifts through all 3 smoothly and the the shift points I'd expect. No need to time her as I'm certian it's well above the 6 sec @ 60 mark... Now I have a knwna lean spot at after-idel acceleration and just to be honest, the one thing we didn't do was degree the cam....Now I have yet to perfromed a compression test, but I know its not burning oil, not smoke and I've got about 20Hg vacuum. I'm litterally at a loss as to where to look...

singerso

Left out an answer to your first question...Yes I drove it all last summer on the previous motor, thus I have a before and after reference as well.Sadly, the difference is negligable. That's another reason why I fell like I'm missing something. Not that I expect this to be a flat out race car, I would have expected it to have enough HP th throw me back and go sideways a bit....

w8less

you need more gear with better heads. heck at least step to gt40 heads

if the car isnt faster then i will send you 50 bucks

Gun Jam

Okay

So it feels just about like it did before you rebuilt it?

The cam, intake, carb are all new but are they any different than the old setup as in are they higher performance?

Does it come on strong and then stop performing or does it feel like it has the same amount of power from 1,500 rpm to 4,500?

Im not familiar with that cam but when it idles in drive at a dead stop does the car shake and everything rattle around like the mirrors and loose change and when you look over the front fenders you can see them rock up and down.....OR is it really smooth like the 05 v8 mustang and has a nice purr to it?

-Gun

singerso

Gun, Pre-rebuild was a stock 289 with cast intake, 2100 autolite and stock cam. The previous owner did a 6 to 8 swap and by the looks of the components used, it was a half *** rebuild. 1 new piston, couple of new main and rod bearings, etc...the only nice surprise was the Hipo block. That said, we guttted and started from scratch with what I consider decent parts. Thus the expectations of much much better performance.

With regard to the cam, at idle she's pretty smooth with a slight rumble. Edelbrock calls this a stock improvement cam (Intake of .448 lift and exhaust of .472 lift) From a dead stop, she is a bit sluggish (recall my comment on lean spot) and at 1500-2500its pretty much the samefrom the power to cruise curve...Not that strong. Just took her out to time her and got a very very disappointing 13 secs 0 to 60..Uhg!

Starfury

First of all, there isn't really such a thing as a hi-po block. There are hi-po main caps and rods, andhi-po marked cranks,but the blocks are the same as standard 289 blocks. Do you have the thicker main caps? Hi-po rods? Is the crank properly stamped? If so, cool, but I have my doubts. A true K-code motor is worth more to someone with a matching K code body than to the average rebuilder.

40 degrees is a lot of total advance. What's the static timing set at? When does the total timing come in by? I'd recommend about 10* @ idle, ~32* all in by 2800.

I've heard a couple complaints about the Performer Plus cam (I'd recommend something muchmore agressive, myself), but it should still be putting out slightly more power than the stock cam. I suspect fuel or ignition setup. Either the timing's not right, or the carb isn't adjusted right. Edelbrock carbs are fairly simple compared to Holleys, but it still requires some skill and finicking to tune them properly. Do you have a full tune kit for the carb? The carb instruction book has a great section on how to properly tune the carb. Takes a while and it's helpful to have someone with you with a stopwatch, but it'll get the job done.

I can only think of two other options:
1) Misadjusted throttle linkage. Make sure that pushing the pedal to the floor fully actuates the carb butterflies.
2) Improperly timed cam

Gun Jam

13 seconds!

with 3.00 gears and a c4, cast iron heads, performer 289 intake and matched street performance cam with carter 600 AFB carb I was getting about 6 sec flat.

From what it sounds based on how your car feels at idle I have a much more radical cam But you should still be getting better performance.

Right now your putting out about as much power to the rear wheels as a bone stock i6 200

you should take a compression test next...if you have the gauge its free and simple, fast too. with my setup I get 140 to 160 PSI with and avg of 150 per cylinder.

If that checks out maybe it is your cast iron head...Sure the cast iron heads will hold your engine back but it shouldn't be that bad...something is seriously mismatched or not properly functioning.

ANOTHER TEST... Pull the valve covers off and watch the rockers arms move and see if they all look about the same. Maybe your cam has some worn down or worn off lobes....even if its brand new improper break in or the like can cause lobes to wear rapidly.

1MORE TEST... Take a good picture of a plug gap for us and let us see the color of the electrode make sure the picture is as close to actual plug color as possible.

-Gun

singerso

Thanks Gun...I'll do a compression test now and get some pics of the plugs..I pulled pne plug and did note that its rich...Soot around the base of the plug, Electrode of light brown and strap is uniform grey...BrB