[HWYSTR455]

When you deck a block the chamfers get cut down, and w large valve heads it can be a problem. That's kind of where I was going with that. It's more of a problem with higher lift cams than what you have though.

There is nothing wrong with using an RPM intake on a 350, people do it with success all the time.

With larger runner heads it can lose port velocity with smaller displacement engines, but still think because of your lift you should be fine.

And good point some others have made that the power range will move higher with a smaller displacement.

I think you will be fine if you have a good gear, min 3.55s, 3.73s would be better, even 3.90s/4.11s for that matter, but you will lose some highway driving comfort.


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[Squidward]

Agree that you should have a fun combo.

Your cam is only a couple of degrees more than mine, 221/229 on a 112, vs mine, 219/227 on a 112. My cam is a touch more lift than yours, but not a significant difference. Very similar.

I can't remember what cc's my heads were, but they were worked, and started at factory spec of 72cc. So you have some extra compression I don't have. Score one for you.

I run a knockoff of the performer rpm, the Crosswind, when it was made by Professional Products. I found it fit better than the actual Performer RPM I had, but it is almost identical except for the heat crossover. Call it a wash.

I run a th350 with 2000 stall converter. I also run 3.73 gears. These crutch the relative softness off idle due to cam, but it is not soft in the way you have described. It screams after that. You have more stall, and 3.55's.

Your timing curve is very similar to mine. I like manifold advance, but that only matters at idle.

I'm just trying to make as much apples to apples as I can. I think your combo sounds very cool.

I agree with previous posters, gotta look at fuel or timing. Did the cam get degreed? What kind of idle vacuum do you have?

I see nothing wrong with your timing curve as long as it was set on a balancer that had accurate timing marks. My best guess is cam timing/timing chain, or carb not set up right. And an out of the box Holley 600 should be a very good starting match.

But don't discount the differences in butt dyno's. Your expectations and definitions for streetable might be different than mine. I am totally happy these days with a 14.0 second car.

[ericwoo]

Originally Posted by b-man

It’s really not that bad at this juncture to build a 400 short block with the appropriate dished piston if necessary to adjust your compression ratio to suit your needs with the heads you have now.

Great idea with the dished pistons- my concern was using the heads on a 400 and being too much compression. Now I just need to figure out how to get a 400 block to build off of. I think it is time to trash this 350. What boggles my mind, is I installed a mild build 302 in a 67 cougar and I was very satisfied with it's torque and hp- it did 14.6-14.8 secs in the quarter mile. I am not sure why a significantly larger pontiac 350 is significantly are worst in power than that.

Originally Posted by firechicken

Is the exhaust system plugged up?

Appreciate the suggestion. It seems to be flowing out the tailpipe well but I could possibly stick my borescope in there to be sure.

Originally Posted by Jay S

Is it possible the converter is not coupling up/slipping?

It's possible. I originally jumped to that conclusion also and threw another $600 to another torque converter and didn't see much improvement. I am now starting to question if there is something wrong with the newly rebuilt 200-4r transmission. Anything is possible at this point in hurting the performance.

Originally Posted by Jay S

The KRE D ports do not have that big of port volumes, 185cc with a 2.11 intake, probably 180 cc with the smaller 2.02 like this has. I have ported iron d ports heads to over 190cc, an aftermarket round port is 210cc, 180 cc is not exactly big on 354 CID. The cam is not that big when the engine is able to pump the compression as high and even as it does, which also suggests the short block is probably ok? It sounds like there must be an underlying issue someplace that is strangling the engine to make power or get power to the ground.

This is good to know. I was thinking my issue was the camshaft, and the heads ruining velocity as discussed in Jim Hands book. These Kauffman heads are said to have 260 cfm flow and apparently my 350 needs to be limited to around 176-196 cfm at max. I am not sure if my smaller valves help meet that cfm limit but the larger cavity cant be good for flow.

Originally Posted by Holeshot71

Like others have said, did you verify cam timing? The 60916 should be installed advanced 4* at 108 ICL. Also, are you sure you are starting off in 1st gear?

Degreeing the cam is the only thing that we didnt do since it was lined up dot to dot. However, I can't seem to think moving it a few degrees will help increase power 50-100 hp. I am still trying to grasp how to check this. I read others say if it is only 2 degrees on a mild build, correcting it want have much performance gain to be worth correcting but I am not too familar with degreeing.

Originally Posted by Squidward

The cam timing is my concern too, assuming other basics have been verified.

OP, sorry it's not working out, wish it was. I've had a blast with my 350P. I didn't want to fantasy bench race with your checkbook, was hoping you could find an easy solution with what you have before the "cube bomb" dropped.

Appreciate your help!

Originally Posted by steve25

Do this simple test out.

1). Get the motor fully warmed up.

2)advance the initial timing at idle until the start has a hard time cranking the motor over, I mean a noticeable hard time.


3). Back 4 degrees of timing off of whatever that is .

4). Take the car out for some full throttle romps while listening for ping .

Are you smiling maybe now after the test drive?

I've done something like this before but tried it again today. I advanced it as far as possible and read 40 initial timing around 500-600 rpm with the vacuum advance plugged up. It still started right up. I drove it around and didn't notice much difference in performance either way ( maybe slightly worse). I'm telling ya this thing loves to start and idle well regardless of what tuning settings are but it doesn't like to perform while driving. This 350 is the weirdest engine I have ever dealt with.

Originally Posted by b-man

However if the harmonic balancer is also original the outer ring may have slipped making it impossible to accurately set the timing. It’s really not an unusual problem actually pretty common. Even new balancers should be checked to verify the TDC mark using a piston stop.

Look at your balancer. Perhaps try a different timing light as well, some are inaccurate..

It's a new high performance balancer. The piston stop was used after is was installed and we actually found the TDC to be off by 4 degrees from what the manufacturer marked it. We scribed the correct TDC mark in it.

Then I double checked it again about a month ago with the piston stop going forward and backwards to find the middle TDC mark and it was correctly scribed right on.

Appreciate all your help. I even checked the compression readings yesterday since getting the heads matched up and they looked good as shown below:

Driver Side Head
Cyl 1: 185
Cyl 3: 197
Cyl 5: 187
Cyl 7: 190

Passenger Side Head
Cyl 2: 200
Cyl 4: 187
Cyl 6: 198
Cyl 8: 185