[Stan Weiss]

Originally Posted by Elarson

The stiff head bridges across between bolts much better and applies better loading out in the unbolted areas.
Separate exhaust ports are a huge help to even out the temperature related distortions.
We had Darton custom-make replaceable sleeves for us so that we could fix cylinders at the track. Reverse Murphy's law....were prepared for that so we've never needed that. Sleeve OD is 4.5 so we only have .12 wall between cylinders but with the solid block, that's ok. The sleeve upper rim has a flat on both sides so they lock into their neighbor. O-ring grooves are in the upper rim of the sleeve. The counterbore depth in the block for the sleeve upper rim is a little short so that the sleeve stands proud of the deck by a couple thousandths assuring that we fully clamp around the cylinder.

Eric

Eric,

From the actual bore size you use. Is there an difference from what the Hemis run?

Stan

[Stan Weiss]

Originally Posted by GTOGEORGE

I’m not sure that Cheby is doing that much better then us there are just MORE of them! SH_T others had to change the bore spacing on the big blocks to make real hp, once you change the bore space it’s not a Cheby any more. We (Pontiac Racers) are set in our ways and don’t like change. Our block is what it is......10 head bolts, 4.62” bore spacing, HELL people (not racers) are whining about the billet, Warp type heads .....it’s not a Pontiac head even though it bolts to a REAL Pontiac block, now these people (non racers) are whining about changing the bore spacing.....give me a break! We’ll never catch the so called Cheby racers we are out numbered and that ain’t changing! PRTTF! ( Pontiac Racers To The Front)!


GTO George

GTO George,
How many all out Pontiac have made close to 1200 HP? SBC 4.40" Bore spacing 400 ci almost 1200 Hp or almost 3 HP per ci.

Since air flow does matter to some degree. Just how much do those warps flow? Yes I know this will not get an answer.

Stan

[GTOGEORGE]

Originally Posted by Stan Weiss

GTO George,
How many all out Pontiac have made close to 1200 HP? SBC 4.40" Bore spacing 400 ci almost 1200 Hp or almost 3 HP per ci.

Since air flow does matter to some degree. Just how much do those warps flow? Yes I know this will not get an answer.

Stan

I just used Warps as an example....Dons RA5 heads can go 530, Warps I’m sure are close to that ....what about Jacks billet head?
It’s a money thing most (not all) Pontiac racers are cheap

GTO George

[slowbird]

Originally Posted by GTOGEORGE

I just used Warps as an example....Dons RA5 heads can go 530, Warps I’m sure are close to that ....what about Jacks billet head?
It’s a money thing most (not all) Pontiac racers are cheap

GTO George

Air flow is only a 1 part of making 3hp/ci.

[bpenrod]

I think Uratchko and Book/Bektash has made 3 hp/ci with SBC and SBM.

[Stan Weiss]

I do not know exactly what the 400 ci Pro Stock stuff makes. I do have a screen print from about a year and half ago of a LS 400 ci engine that made 1168.8 HP @ 9900. No it is not mine.

Stan

[John Langer]

Flow numbers can be manipulated just like dyno numbers. I can say I have an intake port that flows 550cfm. What's the valve size. What size bore was it blown on. Did the port rattle the bench up to .900 lift? Did it move 550 at 1.3". Can you get 1.3" of valve lift. Is the port peaky or does it move good air all thru the valve lift range. We don't race flow benches. Time slips don't lie.

[bendutro]

Ford 385 series are 4.9" bore spacing. At a certain point, brand loyalty just needs to be set aside and run what works.

[bpenrod]

Originally Posted by bendutro

Ford 385 series are 4.9" bore spacing. At a certain point, brand loyalty just needs to be set aside and run what works.

Wider bore space, taller deck height, raised cam tunnel from factory, strong block. 557 ci from a factory block. Kasse is building some great heads for them. Truck pullers have known about them for years.

[mgarblik]

Originally Posted by bendutro

Ford 385 series are 4.9" bore spacing. At a certain point, brand loyalty just needs to be set aside and run what works.

When that decision has been made and brand loyalty becomes meaningless, then 11,000 HP can be obtained from a 500 CU IN piston engine. Current top fuel/funny car engines meet that no brand loyalty mantra and they certainly "work".

[Half-Inch Stud]

Originally Posted by mgarblik

When that decision has been made and brand loyalty becomes meaningless, then 11,000 HP can be obtained from a 500 CU IN piston engine. Current top fuel/funny car engines meet that no brand loyalty mantra and they certainly "work".

I hear that Top Fuel cost $1 Million a weekend, to win a $300 trophy!

[GTOGEORGE]

Flow benches are just numbers....dynos are just numbers....the only numbers that count are e.t. And mph!



GTO George

[455-4+1]

My sons JD engine makes 3hp / CID NA on gas
4 cylinder 4 stroke,
Takes 18,500 rpm to do it though lol
I wonder how scaling up the parameters to 400 cid would look just for giggles ? (well aware of changes with displacement and rpm)

Its a big ask with 2 valves in a Ponty

[455-4+1]

Just for giggles

Small NA engine had B/S of 1.435 and R/R of 2.254 at 3.0 hp/CID
Scaled up to roughly 400 CID (Assume 2x 90 degree banks)

Bore Approx 4.50"
Stroke 3.15"
Rod 7.110"

Not sure about packaging LOL, and obviously apples with oranges, we only have 2v and a single cam, but interesting still the same.
Obviously 18.5k is an issue for peak power LOL

Although the short block parameters are not that helpful, there are plenty of high RPM clues in an engine like this. In my opinion there is alot to be learned from looking at other applications . The oiling system on these has had alot of research, its still a 4 stroke with an internal oil pump and pickup .
Valve train and springs etc are also pretty interesting

[63Banshee]

Originally Posted by tom s

7 years later where are any N/A RA Vs making big HP per CI that has been backed up on the strip?Tom

Perhaps the money hasn't yet flowed in that direction.

[63Banshee]

Originally Posted by mgarblik

The block is important certainly, but don't forget the head bolted down to it. Case in point: Our very tall and stiff billet head has survived at 3000+ HP on both aluminum and iron IA II's for 8 years on one pair of head gaskets. No compression leak witness marks. That's with the stock 10 head bolt layout that everyone said could never be done. Clamp load is what it's all about. 9/16" studs torqued to 135 PSI. A solid head with lots of meat around every head bolt column. Use a light, flimsy aluminum head on an iron block with long, wimpy 1/2" studs at 95 ft. lbs and all you get is 10 pulled-up areas around each head stud and leaks all around, especially where the heat concentration is in the paired exhaust ports. Above 1000 HP, your asking allot of the head gasket IMO. Bore spacing doesn't help, but I am not convinced 4.840, or even 5.00" alone is an instant cure.

I'm not forgetting the head. I wanted to point out the importance of block deck thickness. Something overlooked by many before 60+ boost numbers.

[john marcella]

I so wish people would stop categorizing cyl heads based on its flow numbers.

[Tiger Paw]

Which would you prefer John? Valve size and cross section? Even those won't tell the whole story.

[GTO-relic]

Originally Posted by Tom Vaught

So my vote would be, ALLOW THE BLOCK BORE SPACING TO GROW TO 4.8" and forget about the 'rule" that the bore spacing must be 4.625" to be a "Pontiac Engine." I would love to have a 4.8" Bore Spacing, Short Deck, 4.4" bore, 3.5" boosted engine to play with.

old thread, if I can comment:

https://victorylibrary.com/mopar/bore-center-c.htm

if you want a 4.8" bore spacing, get an AMC, Buick, Ford 385 series, Mopar RB/Hemi, BBC, or Cadillac V8. well AMC and Buick are a tad less.
you want to make Marilyn Monroe into a redhead or brunette....
just go out and get a real one.
It's not like the aftermarket Pontiac engines, or GM block, had serious head gasket problems.
if Butler can put twin turbos on them and make over 3000 HP,
how bad can they be.
realize what you're suggesting...well heck why not an early Hemi with a 4.8" bore spacing.
uh...gee...that's already a 2nd gen 426 Hemi.
why not a Ford FE with wider bore spacing ? uh...that's a 429/460, been there, done that...
the engines that could be widened, were widened. 50+ years ago.
cuz it costs a LOT of money!
would you want to finance and pay for this now ? no. here's why-
grow that bore spacing to 4.8" and it will disenchant and abandon 95% of the Pontiac hobbyists, who run stock blocks.
racing Pontiacs are a tiny percentage of the total market, getting smaller every year.
it's a bad business and marketing idea. good thing no one every acted on this dated post, where would they be now.
most Pontiac aftermarket ventures barely recover their initial investment costs, the way it is.
we'll go down fighting with what's left, until they take gas engines away from us in the near future, under the guise of "carbon control"
it's bravado to suggest you need this 4.8" bore space to make some massive power level,
when you haven't yet taken the existing engines available to their full potential ? such as the stock block, IA block, MRE block ?
have you banged 3000HP out of them yet with twin turbos like some others have ?
if you haven't noticed, guys like Big Chief have beaten modern racing engines having 4.84" and larger bore spacing,
using a stock Pontiac block bore spacing in his own engine.
it's not about HP or gasket sealing when the engines are boosted, it's about clutch management, traction management.
the stock Pontiac bore spacing already makes plenty of HP when boosted, over 3000HP.
have you already split 6 aftermarket blocks up the middle from too much power, that you need this wider bore spaced block ?
I guess the heart of my post is, I reject the premise that you are making so much power, as to need anything more than what's available now.
it's like a kid in the backyard shooting blue jays with a BB gun, saying Dad, buy me a 300 Weatherby Magnum, so I can do a number on these tweetys...
if you wanna make big waves, and deep tracks, bolt a pair of iron RA V heads, on the existing MRE or IA block...
no one has done it yet to my knowledge. you can be the first. get your wallet out. build a 540 IA2 RA V engine.

[quick67bird]

Originally Posted by GTO-relic

old thread, if I can comment:

https://victorylibrary.com/mopar/bore-center-c.htm

if you wanna make big waves, and deep tracks, bolt a pair of iron RA V heads, on the existing MRE or IA block...
no one has done it yet to my knowledge. you can be the first. get your wallet out. build a 540 IA2 RA V engine.

https://forums.maxperformanceinc.com...d.php?t=668432

Ed has already bolted RA V to an aftermarket block. Long thread. The last pages shows the car actually running and avoids the issues he had in the beginning of his build.