[Hooter]

For reference, my street car has a 272/275 @ 0.050 on a 108 in the 467. 3500 converter. Drives fine.

[p4msi1]

Calvin, the ultimate goal with this engine is to have over 900 HP on pump gas and drive sensably on the street. I want to be able to drive at least 1 hour to the local track, race, and drive back. If I have to splash a little race gas to race that does not bother me but I want it to run on pump gas on the street. The 4000 converter should keep the load off the engine to help prevent detination. It needs to run some strong 1/4 mi numbers because I would like to get involved in some of this East Coast Pontiac outlaw racing. It certainly won't be the fastest but, If you want to race with these guys you better bring a BIG STICK and dark sunglasses.

Hooter you running mid 11's with a 272 duration cam?

[Hooter]

Originally Posted by p4msi1

Hooter you running mid 11's with a 272 duration cam?

yeah, lack of a roll bar has kept me from trying to tune it to go any faster. Have only ran it down the 1/4 at Norwalk in less than stellar air too. Weighs 3700.

[65nss4spdGTO]

Originally Posted by p4msi1

Calvin, the ultimate goal with this engine is to have over 900 HP on pump gas and drive sensably on the street. I want to be able to drive at least 1 hour to the local track, race, and drive back. If I have to splash a little race gas to race that does not bother me but I want it to run on pump gas on the street. The 4000 converter should keep the load off the engine to help prevent detination. It needs to run some strong 1/4 mi numbers because I would like to get involved in some of this East Coast Pontiac outlaw racing. It certainly won't be the fastest but, If you want to race with these guys you better bring a BIG STICK and dark sunglasses.

Hooter you running mid 11's with a 272 duration cam?

I don't want to sound negative here, but you are going to have to hit it with a big stick. If you are looking to pick up over 100 HP, it's going to take more changes. Compression and cam, ring pack?

Where did the engine make peak power?

Calvin Hill
Hill Performance
708-250-7420

[p4msi1]

Calvin, gunna raise the compression fron 10.8 to 13.4. Right now it has 30 cc dish pistons and I am going to replace them with flat tops. On the intake side I'm going to 2- 800 cfm carbs from a single 1050. By the way I fabbed the intake with such a low profile I'm thinking that the 2 carbs situated over the runners should make some big gains. Right now the HP peak is 6200, tq @ 4900-5400 kinda flat.
BTW I think I need a roll bar also!
Steve

[cfmcnc]

You can make 900HP with 11to 1CR and the right cam and manifold,WE had a slightly compromised intake on the 892HP combo for hood clearance.1/16.1/16.3/16 std tension ring package,Dyno time was limited as engine had to ship .Bill C.

[p4msi1]

CFM, was that flat top pistons on the 892 hp engine?

[cfmcnc]

Dished .Bill C.

[mysticmissle]

your motor the one with the old dirty bird heads on it? did you try alot of other timing loops?

[p4msi1]

Mystic, I am perplexed on this engine. It seems to have all the goods but just don't deliver. Before I advanced the cam 8 degrees, it only had 130 lbs. (hot) cranking compression. When I simulated the engine on my software it was correct within 5 lbs. On the software program I kept advancing the cam til I could get the most cranking compression practical. In the end it ended up at 8 degrees. I advanced the cam 8 degrees and it picked up power across the whole board and even on the top end. This engine is not gas sensitive at all. I seems to me to be too low on compression with the 30 cc dish pistons.
I did buy the old dirty bird heads but could not use them from all the pinholes. I spent about a day trying to repair them and Dave tried also. I ended up just buying a new set of tigers and Dave Wilcox ported them. I will post a picture of a roughed port.

[slowbird]

We made 900hp with 11:1 compression as well with a 496ci. Compression isnt your issue.

[p4msi1]

Slowbird, what cam were you running? Duration?

[slowbird]

276-286
You need at least another 500rpm to make your 900hp. Your cam timing & engine timing I believe are pointing to issues.

[mike leech]

Originally Posted by slowbird

276-286
You need at least another 500rpm to make your 900hp. Your cam timing & engine timing I believe are pointing to issues.

x2!

[p4msi1]

Slowbird and Mike, so in your experience if I left the compression alone and went with more cam, I should make the power? Are there any specific "issues" or general "issues"?

[mike leech]

Originally Posted by p4msi1

Slowbird and Mike, so in your experience if I left the compression alone and went with more cam, I should make the power? Are there any specific "issues" or general "issues"?

Well here goes best as i can. There could be many things that are hurting you. 1st indicator that something is really wrong is the hp per cfm on the heads. At 440 cfm with the area of the tiger head making 2 hp per cfm should not be an extraordinary feat. 880 is what i would be looking for as an acceptable number. The fact that it requires 39 deg timing is also an indicator. I've helped a couple guys sort out situations like this and heres how it goes...one of 2 directions productive or basically not. The guys who never find it are the same ones that will not actually check everything, they say things like "i know thats not it" or have too much pride to have a pro look at something. Not sayin this is you....but this is were most people are. They will live with a wrong converter or cam because they picked it or its too much work to change in the racing season. Not tooting my horn at all but i sent my converter back 5 times to get it right just this last year. So the moral is its gonna take some work to find it.
Heres what i recommend for a productive plan to find the issue...
1. verify actual static compression ratio. If you are at 13.2/1 you should most likely be beating the bearings out of that thing on pump gas. This is also where i find the most deviation from the specs i'm given at the start. really look at the deck hight and pour the combustion chamber and piston top. You need to KNOW what you have.
2. I would contact a reputable cam guy and have them design a custom cam around your combination. Keep in mind that any cam manufacturer or arm chair quater back is going to have an opinion and try to sell you something. They all think they are experts...most are salesmen trying to sell you something. I use scott at http://www.buyracingparts.com/ Most times he does what i think i would have ordered....sometimes not but the results have been consistently really good. The cam you have is not what i would have picked for your engine and goals btw.
3. Take your heads to a REALLY reputable head guy with a reputation for getting results and have him look at them. there more to it than just the flow bench number.
4. See if you can borrow a tiger or bop intake for testing from someone. Your sheet looks good but there is a lot to consider when designing one. I personally posses the fab skills to make one but would never attempt it because i care about results more than i want to prove i could do it. That said yours may be close....or it just might be 100hp off. It wouldn't be the first time.
5.ensure that all the machine work was done correctly. A bad hone/ valve job etc can kill hp.
6. after all this is done schedule a dyno session with a good operator. If the dyno is stingy even better. But you really want a good operator with a lot of experience that can shed some light if you are having issues while there. Chassis dynos are notoriously off for a lot fo reasons. A bad converter can show a miserable performance loss. They are really good at helping you find things in the car though. If it improves it was an actual improvement in other words.

I hope this helps...

[65nss4spdGTO]

Originally Posted by slowbird

276-286
You need at least another 500rpm to make your 900hp. Your cam timing & engine timing I believe are pointing to issues.

I've been reading this thread and thinking about all of the variables.

I first questioned the dyno numbers, have you been to the track? MPH/Weight/RPM is all you need to know.

Using the dyno information, the engine peaks way to early for a large port 535ci engine. As Slowbird has indicated, 6900 RPM would be a good target to get the piston speed up to over 5000 fpm. That cylinder head with the correct valve train and cam should have a nice long flat torque curve.

Another fact is the low cylinder pressure the engine is building and the need to advance the cam that much.

Again, I don't want to make this sound negative. Big ports generally have poor low to mid lift flow numbers. By design, these types of heads require very specific timing events on the cam and increased RPM to make power.

I would check leakdown, have the cam run on a cam reader and then evaluate my cylinder head flow data before I made any other changes.

Calvin Hill
Hill Performance
708-250-7420

[slowbird]

Originally Posted by mike leech

Well here goes best as i can. There could be many things that are hurting you. 1st indicator that something is really wrong is the hp per cfm on the heads. At 440 cfm with the area of the tiger head making 2 hp per cfm should not be an extraordinary feat. 880 is what i would be looking for as an acceptable number. The fact that it requires 39 deg timing is also an indicator. I've helped a couple guys sort out situations like this and heres how it goes...one of 2 directions productive or basically not. The guys who never find it are the same ones that will not actually check everything, they say things like "i know thats not it" or have too much pride to have a pro look at something. Not sayin this is you....but this is were most people are. They will live with a wrong converter or cam because they picked it or its too much work to change in the racing season. Not tooting my horn at all but i sent my converter back 5 times to get it right just this last year. So the moral is its gonna take some work to find it.
Heres what i recommend for a productive plan to find the issue...
1. verify actual static compression ratio. If you are at 13.2/1 you should most likely be beating the bearings out of that thing on pump gas. This is also where i find the most deviation from the specs i'm given at the start. really look at the deck hight and pour the combustion chamber and piston top. You need to KNOW what you have.
2. I would contact a reputable cam guy and have them design a custom cam around your combination. Keep in mind that any cam manufacturer or arm chair quater back is going to have an opinion and try to sell you something. They all think they are experts...most are salesmen trying to sell you something. I use scott at http://www.buyracingparts.com/ Most times he does what i think i would have ordered....sometimes not but the results have been consistently really good. The cam you have is not what i would have picked for your engine and goals btw.
3. Take your heads to a REALLY reputable head guy with a reputation for getting results and have him look at them. there more to it than just the flow bench number.
4. See if you can borrow a tiger or bop intake for testing from someone. Your sheet looks good but there is a lot to consider when designing one. I personally posses the fab skills to make one but would never attempt it because i care about results more than i want to prove i could do it. That said yours may be close....or it just might be 100hp off. It wouldn't be the first time.
5.ensure that all the machine work was done correctly. A bad hone/ valve job etc can kill hp.
6. after all this is done schedule a dyno session with a good operator. If the dyno is stingy even better. But you really want a good operator with a lot of experience that can shed some light if you are having issues while there. Chassis dynos are notoriously off for a lot fo reasons. A bad converter can show a miserable performance loss. They are really good at helping you find things in the car though. If it improves it was an actual improvement in other words.

I hope this helps...

3&4!

[p4msi1]

Slow, Mike and Calvin, I bought this engine already built and am asking these questions because I have never built an engine of this caliber. I have been building my own engine for 25 years but this whole new combo I felt was out of my league and wanted a professinal to do it. So I did have a professional build it and here I am trying to figure it out $22,000.00 later. I will soon pull the engine and go through it myself. I know Curtis Boggs from RFD and may have him look the heads over. (My sheet metal shop used to be next to his shop in Lorton,Va.) When I first fired this engine up it smoked continuously and blew oil all over the place. The oil pan, valve covers, timing cover all blew oil out. The valley pan would literally fill up with in 10 miles of driving. I removed and sealed the leaks the best I could and bought a vacuum pump which fixed that problem but the smoking problem still existed although it was starting to smoke less the more I drove it. The last time I took it out it lost oil pressure about a 1/2 mi from the shop and now has a knock. Yes, it has plenty of oil, the vacuum pump did not suck it all out, I do know to monitor that. This motor is supposed to have 11to1 comp. but I did not measure it but will. I was wondering if the compression was really low to produce weak cranking comp., 130 lbs., and weak HP numbers. That's why I increased the cam timing, to get more cylinder pressure! My original question is how much dynamic compression you guys have that run on the hairy edge with pump gas. That's where this car needs to be, on the hairy edge. This is a very occasional street car that I want to run good at the track. I have my own dynojet chassis dyno so getting dyno #'s arn't a problem. I also tune other peoples cars and have not had negative feedback most are happy with the results gained. Its a really fun passtime/side job and generate a little cash for the habit. Almost all are stund that their 700 hp small block made 340 rwhp. Mike, I am certainly not too proud to ask as here I am askin and just trying to learn and hopefully will teach someone else down the road.

Steve

[XSIVPWR]

When I first fired this engine up it smoked continuously and blew oil all over the place. The oil pan, valve covers, timing cover all blew oil out. The valley pan would literally fill up with in 10 miles of driving. I removed and sealed the leaks the best I could and bought a vacuum pump which fixed that problem but the smoking problem still existed although it was starting to smoke less the more I drove it. The last time I took it out it lost oil pressure about a 1/2 mi from the shop and now has a knock.

Sounds like this engine had issues from the getgo. Your whole problem could be right here. Eating bearings, and lots of crank case pressure. Sounds like bad hone/bore/rings, my