[Squidward]

^^^ OK, that's interesting. Good stuff.

Hmmm... Previous owner left you with some unknowns. Maybe the cam isn't installed correctly? How would an engine act if it was installed one tooth off on the timing chain? Thinking out loud.

[TAQuest]

The heads are the pre-assembled ones.

It runs good up to 3200 so it's not the timing chain off a tooth.

[NeighborsComplaint]

Low float level.

[68WarDog]

Here's another vote for that being low rpm torque/ towing cam.

[mchell]

Originally Posted by TAQuest

It will rev high but there is no power past 3200 rpm.

This statement sounds like you have a mismatch of parts ......could be any Number of things including your small cam mismatched with Intake, carb, and or exhaust........quite possibly cam installed improperly ( advanced or retarded)

[Scott65]

Full 12 volts powering the HEI?(check it with a volt meter if you're not sure) They will lay over dead like that running 9 volts trying to power the HEI. Don't ask me how I know...

[64speed]

If it’s a 75 400 block it’s not gonna last long enough with that combination of parts for you to worry about octane.....just saying

[TAQuest]

Originally Posted by NeighborsComplaint

Low float level.

Makes sense. Thanks. I have the same carb on my old truck. I'll swap them out and see.

[TAQuest]

Originally Posted by Scott65

Full 12 volts powering the HEI?(check it with a volt meter if you're not sure) They will lay over dead like that running 9 volts trying to power the HEI. Don't ask me how I know...

I'll check that and also swap out the distributor from my other Bird. Thanks.

[TAQuest]

Can you add too much booster and get problems like this?

[Formulas]

Verify carb actually going full throttle with gas pedal on floor, both primaries and secondaries

An engine will rev. freely with partial cfm. in park but lack at wot. with a load

A 2800 cam in a 400 should act real close to the stock 4bbl. 067 cam with a little more torque

[TAQuest]

Originally Posted by Formulas

Verify carb actually going full throttle with gas pedal on floor, both primaries and secondaries

An engine will rev. freely with partial cfm. in park but lack at wot. with a load

A 2800 cam in a 400 should act real close to the stock 4bbl. 067 cam with a little more torque

Yes, I did make sure the carb linkage was working correctly.

Here's the important thing for diagnosing; I have plenty of pedal left. I can jamb the pedal to the floor but it's just like when you run out of pull in 1st gear. It's acting like it at 6000 rpm when it's at 3200. Like there's nothing left. Like the engine has reached it's red line. Just like valve float.

You make a good point at the end. It should run good. We can debate the build. But any small improvements that could be made on the build do not come close to addressing the problem. It should run good or great, not only go 65-75 mph with 3:36 gears. I need to find the malfunction.

[TAQuest]

I was getting 93 octane last year and adding octane booster. It just kept getting worse. Then yesterday, first test of the year, I added another bottle to half a tank. Maybe the fuel in the tank is just bad now.

Here's the deal again;

The engine runs good up until 3200 rpm. I can squawk the tires in 1st and second. No problems until 3200. It acts like 3200 is the red line. Right when you expect the super nice pull it gives up. It doesn't sputter and die. It doesn't go dead like a short. It doesn't act like it ran out of gas. It acts like valve float.
I raced firebirds through the 80's. Got trophies at Mid Michigan Motorplex. I know my Pontiacs. Built a really nice 428 myself. Set up nitrous on it. Had a lot of fun. Never thought I would get stumped like this but here I am. No ego left, just want it to run.

[steve25]

Even if you where running on the primary's only on level ground the motor would still rev well passed 4000 rpm if it can do such out of gear!

As I stated early on here your compression is no more then some 9.2 yet your cranking compression is way high, this and your lack of rev's leads me to say that the Cam was installed one tooth advance by mistake , or a advance key was put in intentionally!

[Formulas]

You have pedal left? Not to beat a dead horse look down carb with somebody on the pedal make sure butterflys are fully open they could be binding also many have reported not so good results at WOT. with edelbrock AFB style carbs

Wouldnt hurt to try different components if you have another carb laying around

In the aircraft industry we called it swapolligy

[TAQuest]

Originally Posted by Formulas

You have pedal left? Not to beat a dead horse look down carb with somebody on the pedal make sure butterflys are fully open they could be binding also many have reported not so good results at WOT. with edelbrock AFB style carbs

Yes, I did that. The secondaries are opening. It pulls good at WOT through the gears but only up to 3200. You can hide the problem by shifting up. It's pretty quick if you keep shifting early. I can get to 60 mph but that's it.

[grivera]

I thought I saw the question asked on this thread already but can't find it - will it free-rev beyond 3200 rpm with no load?

[TAQuest]

Originally Posted by Formulas

You have pedal left? Not to beat a dead horse look down carb with somebody on the pedal make sure butterflys are fully open they could be binding also many have reported not so good results at WOT. with edelbrock AFB style carbs

Wouldnt hurt to try different components if you have another carb laying around

In the aircraft industry we called it swapolligy

I'm a swapper no doubt. I'm going to swap the carb and distributor. I've had bad carbs and distributors many times before and it's just not like that. It seems like the valves start to not work correctly at 3200. Like it has weak springs or something. Like they are bouncing already at 3200. These are preassembled edelbrock heads so it seems unlikely the springs are wrong.

[grivera]

The Stump Puller cam 230/236 would be great with this engine. Here is a good deal on one: http://forums.maxperformanceinc.com/...d.php?t=828503

[steve25]

You do not have any issues to look for in regards to the springs on those heads limiting the motors rpm if it will rev passed 3200 out of gear so stop going back and bringing that up.