[Jay S]

It is great that the head is fixed, disappointing that KRE didn’t make that right. But it should at least have some tuning potential now. Look at fuel and timing timing first. As I said earlier, a holley 600vac out of the box is ok on a 300ish HP engine, or even a 250 hp completely stock 350 with an anemic stock cam and a 4bbl intake. A 600 vac is not friendly to tune compared to other Holley’s, it has a jet plate on the secondaries. Before you give up on the 350, try a better carb. A 400 with that carb will have problems making much power also. There is no mention of where timing is set at, but more timing won’t help much when the fuel curve is already very lean. You would have much better results switching the carb to a qjet or a Edelbrock 750 AVS2, or a tuned 750 double pumper.

[HWYSTR455]

By the time you buy jets & rods for a E AVS2, you're only like $80-$100 away from a Street Avenger. And that's only off by another $100 for an FiTech throttle body efi.

But you would need a tank and lines.


.

[chiphead]

Just use a conversion kit to convert the 4160 to a 4150 so you can jet the secondary side.. Go back to mid-range secondary vacuum spring. The 600 should give good signal and response on that 350. I'd bet the tuning is way off and the secondaries are opening too early, making the engine feel soft. A slightly too-small carb will be more responsive than a too large carb on the street. Install a wideband O2 sensor and report back.

My first Pontiac was a 350 in a '67 Lemans, they can run.

[Jay S]

I said 750 ASV2, but that does not exist, the ASV2 jumps from 650 to 800.

[ericwoo]

Appreciate the responses but I do not think this is a tuning issue. I have adjusted the timing and carb mixture so many times without any drastic improvement. And even switched out the carb to a larger 700 and nothing seems to help. Oddly enough, even purposely tuning it wrong, doesn't seem to negatively effect the performance much. I mean it runs fine for folks that want about a stock performing slug.

Mixture was adjusted by getting max vacuum and checking the spark plug burn lines. Full timing is about 32 degrees around 3,000 rpm.

The car overall starts and idles perfect but there is literally no bottom end torque in this thing which is quite shocking considering the stock 350 with a 2 barrel carb is said to have 355 lb-ft of torque.

Even the upper end horsepower is not really impressive even for a car with only 6 cylinders IMO. My 350 only seems to create a little bit of power in a very short power band around 3,500-4,500 rpm.

If I had more than 300 horsepower and 300 lb-ft of torque in this thing, I would be surprised.

I really just think it is a bad choice of camshaft, too much flowing heads and too large of volume intake manifold which ruins port velocity. I can thank the head manufacturer for those terrible suggestions.

Anyway, I was really just asking if anyone thinks I can salvage the use of these expensive heads by using them with a different intake manifold such as the Performer instead of the RPM Performer.

I'm at a crossroads of selling the whole car out of frustration, spending money to get the stock heads worked on and installed, or buying a 400 engine.

[b-man]

I would put a stock Quudrajet intake on it. Iron or aftermarket aluminum HO / Ram Air, both functionally equivalent.

Switch to a recalibrated 1976 or later 800 CFM Quadrajet. The 800 will only feed the engine whatever air flow it asks for, late ‘70s smogger 350 engines came standard with them.

Did you try bumping the timing up to say 36-38 degrees ?

Or did you just settle for 32 ?

[ericwoo]

Originally Posted by b-man

I would put a stock Quudrajet intake on it. Iron or aftermarket aluminum HO / Ram Air, both functionally equivalent.

Switch to a recalibrated 1976 or later 800 CFM Quadrajet. The 800 will only feed the engine whatever air flow it asks for, late ‘70s smogger 350 engines came standard with them.

Ok, I will check them out but do want to be sure it will help before continually dumping money into it without having much improvement. I am still surprised the performance isn't much better after getting the driver side head milled down correctly to match the passenger side.

Originally Posted by b-man

Did you try bumping the timing up to say 36-38 degrees ?

Or did you just settle for 32 ?

Yes, I believe I even tried up to 40 degrees advanced. It seems this engine is pretty forgiving on running decent when the timing is adjusted quite a bit whether it is retarded too much or advanced too much. There may be a slight performance difference but not much to really noticed much of a distance.

[firechicken]

Is the exhaust system plugged up?

[b-man]

So at this point it looks like you’ve bolted a nice set of aluminum heads/RPM intake and slid a decent cam into a used stock 2-barrel 350.

You followed what the ‘experts’ advised and ended up with disappointment.

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.

On the street cubes are king, the bigger engine will have better manners than a high-strung small one. You already have some good heads so put them on the 400 you should have planned to go along with them.

[Dragncar]

Put a 4.25 arm in a 400 block or find a 455, use your stuff. You will be happy.

[HWYSTR455]

Only way to get bottom end in small(er) displacement engines is more SCR or gear, and even then it's a 'compromise'.

'There's no replacement for displacement'.



.

[Jay S]

Something seems wrong somewhere. It should have much more power than it does. The small carb should at least have good power at the 2800 RPM converter flash. Is it possible the converter is not coupling up/slipping? The small carb should at least hit the converter harder even if it is short of top end power.

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.

If there is an underlying issue in the short block creating trouble and you want more power, like the others said, don’t do a 400, do a 400 based stroker with a 4.25” crank or find a 455.

[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?

[johnta1]

With the 3.55 gear, that should be a peppy car.
I'd check the tranny/converter for any problems.
As said is it in 1st gear?
Don't know the gear ratios of the overdrive tranny, but would think it's a lot lower 1st gear than a TH350?
It should be like a beast coming off the line. (even 4 cyl cars with them move good off the line)

[johnta1]

Just checked the 200-4R, it has a 2.78:1 1st gear. That is not so good for an overdrive tranny? At least you need a little more rear gear I think.
3.73 maybe or 4.11?


The 700R4 may be a little better tranny if needing an overdrive tranny.

[Squidward]

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?

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.

[b-man]

Originally Posted by ericwoo

Ok, I will check them out but do want to be sure it will help before continually dumping money into it without having much improvement. I am still surprised the performance isn't much better after getting the driver side head milled down correctly to match the passenger side.



Yes, I believe I even tried up to 40 degrees advanced. It seems this engine is pretty forgiving on running decent when the timing is adjusted quite a bit whether it is retarded too much or advanced too much. There may be a slight performance difference but not much to really noticed much of a distance.

Your 65k mile 350 short block may be in good shape and your really should be running better than what you’re experiencing.

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.

Plenty of folks have had nice running 326 and 350 engines.

Your heads are similar in airflow to the 5.7 LS1 heads which are a 260 cfm head. Those engines make 1 horsepower per cubic inch (346 cubes) and easily propel a 3600 pound car into the mid to low 13z factory stock with a rather small 196/208 @ .050”, .467”/.479” cam. Throw a cam similar to your 60916 into that LS1 and they really wake up.

Your 200-4R 2.74 low gear combined with a 3.55 should move out nicely, a 9.727 ratio. It compares well with the 3.06 low 4L60E and 3.23 my 2002 WS6 came with, a 9.8838 ratio. By the way the standard LS1 cars had a 2.73 rear. So I don’t see any issue with your choice of transmission and rear end gear.

I still think there’s some kind of serious basic tuning issue here.

I had a mild low-compression 8.6:1 bracket race 455 that I was just beginning to get onto the race track. In my first few outings I conservatively set the timing at 30 degrees. I couldn’t get the car into the 12s, it was stuck in the 13.0 area.

As soon as I bumped the timing to 38 it instantly responded with a 12.60 time slip. The combination of low compression and the high altitude track (2700 ft) required a lot more timing advance.

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

if you do end up building up a new short block with more displacement just be aware that your small 59cc chambers and smaller valve sizes might be a better fit for a 400 or possibly a 428 short block due to the size piston dish required to get a reasonable pump gas compression ratio. Actually the valve size isn’t much of an issue at all it’s the small chambers which might require a pretty cavernous piston dish (reverse dome) to be used on a street 455-type engine .

Once you work out the compression numbers you can decide whether to keep the 3.75 stroke 400 crank or go for a 4.00” or 4.25” crank in your future 400 block.

[tom s]

Put the new supercharger system on it that John Cogger has designed for our Pontiacs that fits under the hood.It will scare you then.Tom

[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?

[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