[65nss4spdGTO]

Originally Posted by Scott Roberts

Where would u put the range on s 451 with 450cfm.heads

What is the stroke?

Calvin Hill
Hill Performance
708-250-7420

[Scott Roberts]

Originally Posted by 65nss4spdGTO

What is the stroke?

Calvin Hill
Hill Performance
708-250-7420

Say 3.75...there also ways to help with the offset and the push rod angle..

[Jack Gifford]

Originally Posted by Half-Inch Stud

... a 450cc (22.5 CID) 2-Stroke...

450 cc is a little over 27 c.i.
In any case, this thread is not about HP/c.i. of two-stroke engines.

[455-4+1]

Just replying to HIS question

Its a Honda CBR250F. (just over 15 CID)

4 cylinder 4 stroke with real valve springs
Seems weird setting a shiftlight at 16k to get a shift in before the 18k limiter LOL

Back to topic........................

[65nss4spdGTO]

Originally Posted by Scott Roberts

Say 3.75...there also ways to help with the offset and the push rod angle..

9400 to 9600 RPM, 2.3 HP to CI on a 451ci= 1037 HP.

That engine will still need to be making big power @ 10,200 RPM. I would like to hear that sound coming from a Pontiac.

Calvin Hill
Hill Performance
708-250-7520

[Half-Inch Stud]

Originally Posted by Jack Gifford

450 cc is a little over 27 c.i.
In any case, this thread is not about HP/c.i. of two-stroke engines.

Actually, Strong relevance in spinning 9000+ RPM to attain 2X HP for a 4-Stroke engine is;

on par with the 2-Stroke of same CID running at half RPM.

Shows the true cost of >2X HP/CID is (Valvetrain) spin-ability for us Joe 6-packs.

Indicating a dire need to implement a desmodromic valvertain.

If no desmodromic, THEN a NECESSARY begging need to vent the Exhaust through a WINDOW, not a valve. And run a larger Intake valve.

That my friends leads to oiling & bearing technology swaps to avoid crop-dusting along the 1/4 mile.

So, for an attempt at keeping an exhaust window clean and free of traditional oil, i'd like to know if CYL coatings, and accommodating piston skirts eve have a chance to run in an exhaust-windowed block. If not then i want to know if fuel-like lubricants can keep the traditional V8 bearing system survived under Topic loads. If neither can support, then the transition to caged needle bearings on piston pin, rod journal and crank are a development trade for us low-buck enthusiasts.

I hope this serves to summarize the potential developments avenues yet to succeed 1000lb exhaust valvesprings and accommodating valvetrain & block expense. on topic? HIS

Probably worthy of a separate Thread, or forum, so I'll bow-out of this & just read.

[dci]

I think we all agree it will take an rpm level that most traditional Pontiac enthusiast don't feel comfortable at. So I think that is the first hurdle we need to address. The second hurdle I see is the valve train. To make this level of HP we are going to need a cam lobe that is very aggressive. With a two valve head design that is going to require a valve spring of the highest quality and will most likely need monitored every pass. At the very least you may need to change one or several every couple of passes. A valve spring of this caliber is not cheap and will need to be ordered in multiple sets not just one set.
I'm not a hundred percent sure how many, but I do know that Pro stock engines have more than 5 cam bearings to keep the cam from flexing. So we are at an immediate disadvantage right from the start. The very least that we need to do is have a bigger cam core at least 60 mm. That will take some creative block machining to make it work. I think that we need to look at average cfm in the window that the cam operates in to estimate HP potential not just peak cfm. I agree it will take close to 500 cfm to attain this goal at max lift, but the flow numbers at .400-.500 through the cams max lift will need to be scrutinized. This will need to be done with the intake in place when testing or all of your effort will be wasted. I have seen a poorly designed intake knock over 100 cfm out the head.
I think the 4.400 bore x 4.100 stroke combo is definitely doe able and rotating weight can be controlled. I also think this stroke will need around 8800-9000 rpm with a cylinder head csa that will support the amount of cfm needed for 1150 HP. This will take allot of R&D on the dyno with different port designs and cam profiles.
We still need to address intake runner length, taper, csa, plenum volume, and carburetor locations. We also need to look at header design. I'm sure someone here has a program that can estimate header diameters, lengths, and collector selection. I don't have any of that fancy software LOL. When we all agree on what this engine will need. It would be cool to have someone plug it into a sophisticated and accurate simulator to see what we get.


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

[65nss4spdGTO]

Originally Posted by Scott Roberts

there also ways to help with the offset and the push rod angle..

Very true, maybe I should send these short deck blocks for furnace welding?

Calvin Hill
Hill Performance
708-250-7420

[J.C.you]

With a cyl head with the right valve arrangement, one could get by with a lot less than
.220 between cyls. and increase the bore more than 4.4.

Nascar engines regularly approach and sometimes eclipse 10k rpm for 500 miles, to 600 miles. Lifter bores, cam lobes can be moved, cam tunnel raised and enlarged.

[cfmcnc]

Exactly J.C.You...your piece showcases some of that thinking and ingenuity doesn't it!!
This stuff has been done in every other brand X form...heck it's even been done here in the Pontiac community a couple of times . The block we have here is 4.435 bore . and I know someones block is even bigger than that! We're at 2.0 per and less than 8,000 with Frank's deal (7,300 for peak power) . This is very , very possible. Johnny

[Pont428]

Originally Posted by J.C.you

With a cyl head with the right valve arrangement, one could get by with a lot less than
.220 between cyls. and increase the bore more than 4.4.

Nascar engines regularly approach and sometimes eclipse 10k rpm for 500 miles, to 600 miles. Lifter bores, cam lobes can be moved, cam tunnel raised and enlarged.

JC, I heard you were going back on the dyno? Lynn told me your engine is a 1300HP plus engine with a sheet metal intake and a dual quad on it. That is pushing 2.14 HP/CU. It is way harder to get HP/CU the higher you go in cubic inches.

I have heard McCarty Racing is doing a 406 and it should be in the range of 2.7 to 3.0 HP/CID. It has a 4.40 bore and 3.3 stroke. I think that comes out 404 and change. They intend to run NHRA Comp Eliminator or at least Super Stock Modified. I saw the crank, man is that thing cool! It is an old original RAV forging from a 366. They have two of them!

My McCarty Racing engine is nearly 4.600 bore and 4.8500 crank if we dont find a tall block. I cant wait! I am posting some pictures of RAVs sent out.

[KO]

Originally Posted by Pont428

JC, I heard you were going back on the dyno? Lynn told me your engine is a 1300HP plus engine with a sheet metal intake and a dual quad on it. That is pushing 2.14 HP/CU. It is way harder to get HP/CU the higher you go in cubic inches.

I have heard McCarty Racing is doing a 406 and it should be in the range of 2.7 to 3.0 HP/CID. It has a 4.40 bore and 3.3 stroke. I think that comes out 404 and change. They intend to run NHRA Comp Eliminator or at least Super Stock Modified. I saw the crank, man is that thing cool! It is an old original RAV forging from a 366. They have two of them!

My McCarty Racing engine is nearly 4.600 bore and 4.8500 crank if we dont find a tall block. I cant wait! I am posting some pictures of RAVs sent out.

What heads for Super Stock Modified?

[pastry_chef]

Originally Posted by Pont428

I have heard McCarty Racing is doing a 406 and it should be in the range of 2.7 to 3.0 HP/CID.

LMAO!!!

It will NEVER happen!

[Scott Roberts]

Originally Posted by pastry_chef

LMAO!!!

It will NEVER happen!

Agreed...not with a tunnel port. It has been proven by some of the best in the racing buisness that a tunnel port wont work in the high rpm range..9200-10k+. some years back, millions were spent testing tunnel ports for prostock. They scrapped the whole program.

[BruceWilkie]

Originally Posted by pastry_chef

LMAO!!!

It will NEVER happen!

Agree... there is good reason the tunnel port isnt in use in pro stock. It aint money.

[J.C.you]

Originally Posted by Scott Roberts

Agreed...not with a tunnel port. It has been proven by some of the best in the racing buisness that a tunnel port wont work in the high rpm range..9200-10k+. some years back, millions were spent testing tunnel ports for prostock. They scrapped the whole program.

Since you are privy to the tests, did they test with the pushrod in the port or out of the port?

Don't get me wrong a inline valve is not on the same playing field as a current prostock layout and that high of hp per cube is stretching it.

[Scott Roberts]

Originally Posted by J.C.you

Since you are privy to the tests, did they test with the pushrod in the port or out of the port?

Don't get me wrong a inline valve is not on the same playing field as a current prostock layout and that high of hp per cube is stretching it.

It wouldn't be a tunnel port if the push rod was out of the port..

[J.C.you]

Originally Posted by Scott Roberts

It wouldn't be a tunnel port if the push rod was out of the port..

who says

[Scott Roberts]

The term "tunnel port".. what do u think it refers too?

[J.C.you]

Originally Posted by Scott Roberts

The term "tunnel port".. what do u think it refers too?

I have driven in a few tunnels in my lifetime. No pushrods in those. Seriously, tunnel means straight in my thoughts, not if it has a pushrod in it or not.