That's alot of hp for a N/A 306. :cool:

yes it is...
 

Yeah, but I am basically possesed and will have the dyno sheet to prove it by July.
I may be living in my garage by then, but my car will be fast!

well, one thing... all dyno's arent the same... I've run the car on one dyno, made changes that picked up over 2mph in the 1/4.. gone to another dyno and put down 12HP less after the changes...
here's my last run with my car.. AFR heads, stock cam, 1.7's, BBK headers performer intake and a 600 holley... all the emissiosn stuff is on the car... run 102.5 in a 3400 lbs. car 90+ air temps ;-)
actually, I can the same MPH when it was 106* out ;-)

You are right
 

You are right about dyno's not being the same, but I know my cam is not carrying me to RPM. Anyway, I'll post so others can learn from my pain. Can something really be so painful and fun at the same time?

I remember having a low peak power problem. It turned out to be badly worn valve guides in my TFS heads. After the guide fix peak power went from 4900 RPM to I think 5200-5300.

Then I switched to the Holley and peaked at 5800 rpm, and layed down 20 more ponies to the wheels over the GT-40 with the ported lower (to a 1262) Like 1BAD89 said, I picked up a consistent 2 mph on motor and 3 on the spray.

Valve guides...
 

Will check the entire valvetrain to be sure. What mileage did you have after you discovered your bad guides? But I suspect right now that the cam is my major issue.

Looking at that graph, its very jittery up top. You said it your self that the engine has a miss. Now, you have to do some checking/testing to see what is causing the miss. What ever is causing the miss is causing you to lose power. I'm no expert, but i've been in your shoes and it sux. It sux when u have all those fancy parts and somethings wrong causing u not to get the most from your combo. Are u getting good spark? Fuel? Do u have a fp gauge that u can see at all times, preferably a cowl mounted mechanical one? This way u could see if fp is dropping.

I had a problem with my combo. I went to the dyno and only made 275rwhp/316ft/lbs and I was like WTF, My combo should be making more. Just recently I found out that all along my fuel filter was on BACKWARDS!! This was causing my bad dyno #'s and track times all along. I havent re dynoed, but I did gain a full 3-4 mph at the track which is a big difference for just a filter. My graph wasnt jittery like yours, but I did only make pk power @ 5100, which is low. It fixed now, just needs some tuning.

I agree with some of the other guys, that B303 cam isnt great, but its not the reason for your bad #'s. You have a miss and you have to find out whats causing that miss. Good luck man, I know how it feels!! I'm glad that it only cost me $10 to fix my combo, I hope its just as easy for you!

Mike

Umm... hate to point this out guys, but he's running 1.7:1 roller rockers on that B303.

.510/.510 and 224*/224* duration is more than enough cam to make plenty of top end power. There is nothing wrong with the cam. If I'm correct, the GT-40P crate engine is rated at 320hp with a B303.

You're about 30-40hp short of where you should be. 255rwhp = about 310 at the crank. You should make around 340-350 at the crank with your combo, which would be around 280-290rwhp. If you bumped the CR, switched to a 76mm MAF, a 70mm T/B, and got a different intake, you might be able to see your 340rwhp, but that's about 410 at the crank. 410hp N/A with an EFI 306 is a pretty tall call, but with 10.5:1 you might be able to pull it off.

With TFS TW heads, the last intake test I heard about had the Holley absolutely trouncing the other intakes. I would certainly recommend it for max power on your combo.

Was the Dynojet equipped with a load bearing device? If not, forget about the correction factors. They aren't whats messing with you. In fact, the dyno may not have any adjustable correction factors depending on the model.

You know you have a misfire, and obviously that's top order. Hey, exgmguy, weren't your heads older model TFS's before the change over?

TFI woes...
 

After several diagnostic evals today at the shop, best guess is a bad TFI module. I have now idea how to test it, but I am looking for a replacement for my Mallory unit. I have read several TSB's about heat and heat-sink related failures, some recommending changes as frequently as every 30000 miles.
Oh yeah, my new NAPA fan clutch (2000 miles old) is frozen, there's 15 hp right there. Just noticed it today, free revving the motor. How's that?
Now I need good recommendations for an electric fan. Thinking Flex-a-lite...

Re: TFI woes...
 

Good idea, I really felt every bit of 10-15 hp off an electric fan, I was pleased....btw my friend has a carb setup tf head, bcam 347, it makes about 375 at the wheels, but with 10:51 compression, and port worked heads, pulls to 6500 no problem, you engine just needs some test, it's all about hotrodding:)

TFI test...
 

Got a replacement Mallory TFI today. Will be installed in an hour or so, then a test run. Electric Fan tomorrow. Dyno run Tuesday.

Let us know how everything turns out, hope it solves it. :)

Your cams fine. Your motor combos fine.

Look at your dyno graph, ITS ALL OVER THE PLACE.

FIND out whats causing the miss, theres your problem.


I see 285rwhp after that.

Skyler

TFI module...
 

Just put it in, TFI that is, car warming up now. Lot's of heat-sink compound and dielectric grease. ...Stand by!

I run an electric fan from autozone with no cooling problems whatsoever. Just ask for the biggest size they have, I think its something like 21". also be sure to get a quality toggle switch for it because the one that comes with the fan is junk.

Oh yah, this fan is only like $65-70 compared to close to $200 for a black magic fan.

just throwin some info out there.

good luck with it
-Drew

TFI didn't fix...
 

4800-ish "lean" type miss is still there. Tried new TFI and that means everything electrical has been replaced. Double checked plugs, wires and timing. No luck. 10-14* timing and 38-42 PSI no joy.
I am planning on pulling the intake and injectors next.
After that, the cam will come out if that's not it.