Big Cubes vs. Small Cubes

Brian,

Interesting comparison between Bruce's 494 and this 464 that you just dynoed.

An out of the box style Stg 2... depending on what out of the box is... will result in a peak flow number of 270 to 290 cfm. So.... if we go by the rule of thumb of 2.2 hp per cfm your results would be 270 x2.2 = 594 ph or 290 x 2.2 = 638 hp. I have seen a very good engine produce around 2.4 hp per cfm so lets say 270 x 2.4 = 648 or 290 x 2.4 = 696. So the hp numbers between the two engines are fairly close.

The BIG difference in the numbers you have posted is the torque. Bruce's engine makes 657 and this 464 is making 620 ft lbs. That is 37 ft lbs of torque.... that is a huge difference. I dont know what that would equate to in ET but I would think you would see a big difference.

It seems it would be safe to say that HP is pretty much based on the amount of air the cylinder heads can flow but the added stroke would definately increase the torque??? Which in turn relates to quicker ET???

All I know is that when I hit the lottery.... we will all know the answer to these questions!!!

Later

 

On the first point, I think there is alot more to it than that. Which I'm sure you're aware of.

I disagree on the second part. The added stroke will increase torque in lower RPM's, yes. That won't necessarily make for for a quicker ET, and if you tune it to the max it probably won't result in a better ET. I believe in making the most horsepower you can, which means RPM's too, and use the gearing and converter to get it moving. This is all within reason, of course. You need a certain amount of low RPM torque to get a 3600 lb car moving. But, out of the two engines compared above, I would choose the 464, and dial in the converter to make it launch.

Check your datalogger and find out how much time you really spend in the lower RPM range. What good is low RPM torque if you never use it?

This is a very interesting thread. We haven't had one of these in awhile.

Just my opinion. Have fun.

 

Is the stock rod length used with these bigger stroke combinations. I have had an crank offset ground and would like to know before they put it in the block if there is a need of changing the rods.

 

how many people are running stage 4 heads in a serious n/a appliction? The reason I ask this is because we seem to compare stage 1 2 and 3 headed engines with the big inch strokers and the volume of these heads especially the pinch area is too small. you can get good flow numbers with these heads but if you cant feed the volume the engine won't use the cfm to it's potential. The stage 4 head on the other hand has more cross sectional width in the port to more adequitly fill the cubic inches.If money would allow me to experiment with this I would,so any feedback from someone who has would be interesting ?

 

What kind of flow numbers did these heads have? What was the compression on the 464?
________
Yamaha Ox99-11

 

The rod length typically will vary with the different stroker combinations. When you are building a stroker, the piston and rod are both aftermarket anyway, typically not the stock Buick length. There are alot of factors to consider when doing a stroker. Jim Burek

 

The 464 is 11:1 compression and the cylinder heads flow 290cfm. The 494 was just shy of 12:1 compression. We never had the 494s cylinder heads on the flow bench.

 

Bore and head flow

Has anyone checked to see what the gains are with the 4.500 bore on the flow bench for a Buick head? I know there are guys like myself with the Stg 3 2.25 valve in the small 4.350 bore which can be tight. I know that there has been alot over the years with the right valve to work with the bore and I've never seen the 2.25 valve not hurt the 4.350 bore but will that change on a 4.500?

 

Thanks. Those are some amazing numbers for that head flow and compression!
________
Lovely Wendie

 

We have tested the cylinder heads on as large as a 4.600 bore with no noticeable flow difference.

 

Rick I tested with a 4.45 bore and a standard bore. no big gains, however we did cut the valves down to 2.22 for the stage 3 heads. they flow over 300 cfm at only .400 lift and max out at just over 360. no messing with the head bolt boss.

 

I know its apples and oranges...but...Top Fuel motors are less than 500 cubic inches and make 6000+ horsepower. That's just mind boggling. They also use a 3.23 (i think) gear ratio.

Just wanted to throw a curve ball at everyone.

 

Hey guys,
This has been an interesting thread . My buick is just street car. My race car is basically a 500 inch pro stock car less about 40 cubic inches. It has an ultra short deck(9.200) big bore (4.622) and a baby stroke(3.41) . The problem with the IHRA stuff is inefficiency. The run undersquare(bigger stroke than bore) and they are just plain heavy. The best way to accelerate a drag car is to make it light . Same thing with the rotating assembly. The tall deck of the new Buick block, although you can go to a bigger bore will still leave a heavy rotating assembly --longer rod ,pushrods etc.
The heads on my race car flow over 500 cfm on the intake side. I shift it at 9200 and go through the lights at 9500. I can do that because the stuff is lite and the bearing speed is low. The mains are BBC but the rods are Honda size. The crank is a winberg and it is tiny(never weighed it)
Big bore capabiltiy is great but a 4.5 x4.5 motor is a really good motor for a boat. Lotsa torque.
Here's the bad news on my stuff.
Rods every 50 runs
valve springs every 10 runs(about $400 a set)
Kills jesel rocker gear pretty regularly( Intake lift close to an inch)

I think the new block is a cool thing but I think the other short comings ( one combo works and another doesnt) will appear when the motors start to get built.
Good luck guys
George

 

Ouch!! I need to stay away from that! :shock:

 

Comp Donkey Is Right!!!!!

Yes, the famous comp donkey :sleep:This thing can't spin the skin of a grape! This guy was all cocky about this new stove, he was going to set the world on fire, and get him deep into the nines. This is just a mini pro-stock motor, dry sump, vacuum pump, sheet metal intake, dual dominators, and the roller cam is huge in this thing, he tows it back from the end of the track to save the valve springs that are good for about thirty passes. When he went to get his NHRA licence so he could run the nines. The car wouldnt even get into the nines, and has earned the nickname comp donkey at the local tracks. Adam's car is heavier, makes less power, and is a street car. I have personally driven Adam's car on the street, and it runs the same number as the comp donkey... low tens. If I was this guy, I would retire from drag racing and take up knitting. There is no replacement for displacement. Chris

 

I understand what you guys are saying but this sounds like a combination problem. My motor makes only about 850 ft of torque. If I put that peaky thing in a 3000 pound car it would be a dog too. The camshaft is wrong ,too much port volume,etc.
On the flip side there is super modified class in comp which is probably one of the most expensive classes in comp that has 2700 to 3100 pound cars with small cubic inch small blocks. A/supermods are in the eights with splayed valve small blocks, two carbs and five speeds.
I see that this fellow is having trouble but that might be his issue not that it cant be done .
Comp is one of the most difficult and expensive sportman classes in drag racing and this is why the class is in trouble going forward. There arent many newcomers and fans dont get it .When I tell people I run comp they think "super comp" and when they see it from the stands they dont understand what "index" racing is.
I can tell you from the drivers seat that its about $150k difference. If your not ready to spend that kind of dough and gather the knowledge base to race comp there are too many other classes to have real fun with. Sometime I miss hanging out between rounds and looking at other cars in the staging lanes or whatever.
By the way, if that thing is an 11,000 rpm motor and he only swaps valve springs every thirty runs , then his whole program is off track. Its not just lift its also harmonics and stability that kills them . Our stuff shows a drop at the seat after one pass.At ten we swap the exhausts to the intakes and put new springs on the intakes and throw those ten pass old intake springs in the trash.
By the way those springs are about $370 a set.
Should I tell you about our clutch maintenance ?
Have fun .
George

 

By the way,
the bore and stroke that makes the 572 combination is a good marine application.That doesnt mean it wont work at the dragstrip. For raw hp the 540 and 555s tend to outperform. With this new block you are getting into Big block chevy combos and studying those might help.
good luck
George

 

Cam Shaft

I told "big head" when he bought the comp motor that the cam shaft and heads wouldn't work with his combo but he just looked at me like I had 3 heads o No: I love running side by side with the comp donkey :laugh: I'm the same weight, stock block ,crank,rods,Ta intake and 2" headers,308s cam,1 carb not 2, stock stroke.....ok ok I'll stop now..George,I hope you under stand are respect for comp racing, we love the class.This is a great example about how having the wrong combo can slow you down big time. If you met this knob at the track he would tell how fast and wonderful he is, the time slips don't lie........Chris

 

I hear ya.
There is so much to getting these combinations down the track.They are not for the faint of heart.Thats kind of why I like my Buick. Its strong ,runs all day at 180 degrees and punishes the tires pretty much at will on 93 octane.
I am thinking about dointg a set of stage II heads to help the car handle and give it a bit more power upstairs.
Is there a stage II shorty header? My car sits pretty low AND is a 5 speed. Linkages might be a problem with a big tube header.
Next time you see your buddy give him two words--Clutch management
Take care
George

 

George there is a shorty header from ta performance I think you can get it in 2''. our buddy tom from alberta runs them on his streetcar and it runs real strong for how mild the combo is. it runs 11:50's on pump gas with a tiny little cam ,steel wheels,3:73s and not much else. :3gears: