On the dyno Friday (the first of 6 identical units), delivered Saturday, it's already in the car. A 406" SB based on a Dart block, Ross pistons, with 23 degree (235 cc-in house ported) Pro-Toplines, a Blue-Racer solid roller, Blue-Racer 1.6/1.5 Rockers, Eagle 4340 (internal) crank, 5.850 rods and a "nylon" timing gear set. Super-Victor and a 4500 Holley. 10.95 (measured) C.R. Runs fine on 93, customer will be using 100 unleaded for racing however. Made 580 HP @ 6600 and 523 Ft.Lbs. @ 5500. The main reason for posting these results is to show that the mfr's. are not always "right-on". The ring gaps
in this unit are .018" top and .013" second, with low-tension oil rails. There is no vacuum pump, nor are the Ross pistons anything special (e.g., no gas-ports, etc.), right from the box. The "quench" area is huge. P/Deck is .032" and Corteco head gaskets are .038". We have a total of 34 degrees timing for the entire test. No problems at all. Only requirement was 2.000" primaries, it wanted nothing smaller, this was the only other item (header size) we had time to test, in order to make the delivery schedule on time. Thanks, Gary in N.Y.
P.S. There are NO "fancy" parts in these units, everything from the boxes. The next ones up will recieve a bit more "flogging". 2 of the remaining 5 will see 6.000" rods. We see 600+HP (on 93) around the corner. The heads performed flawlessly. These 400's will certainly be a "ride". Real nice combo!

I'm missing the part about how manufacturers are not "right on" - could you go over that again?

Thinking of an engine as an air pump, the header sizing should be related to the power level. I might have expected as good of results from 1-7/8" primary tubes - but every engine combo has different needs.

Stout number at a reasonable rpm, should work well.

Thomas

SO.......what's your point Gofast?

SO.......what's your point Gofast?

Three points here, first the "quench" (.070") has absolutely no effect on the overall performance of this particular unit, and second, some builders up here have been listening to the mfr's. saying run the second ring with much wider gaps than in the past to help the top ring seal better, with the numbers we have on this unit and the rings being as tight as they are (.013"), we feel there's a point where the gaps on the 2nd ring will start to contribute to excessive "blow-by". We have dozens of units out running with these "close" gaps and still making excellent power and "zero" blow-by, and third, you don't need $3000.00 CNC'd "brand-name" heads to pull it all off. We've had many good units out the door with these "Pro-Toplines". Thanks, Gary in N.Y.
P.S. This unit is already scheduled to be returned in about 6 months to have a blower installed and at that time we will make the necessary corresponding cam change to go along with the blower installation. This was one reason we decided to leave the "quench" where it is now. These are totally respectable numbers for a 400" N/A SB on 93.

P.S. This unit is already scheduled to be returned in about 6 months to have a blower installed and at that time we will make the necessary corresponding cam change to go along with the blower installation. This was one reason we decided to leave the "quench" where it is now.

Hi Gary,

Does the quench not matter as much on blown engines? I ask because I have no quench in my motor because the pistons are a bit down in the hole and with my 177 I always wonder about it.

I found this on the Ross Pistons website for their blower pistons and was suprised:

Lower compression ratio is achieved by utilizing more deck clearance then normal (flat top "down in the hole") and is based on 64cc heads.
Compression ratio based on 9.025 block height with .042 head gasket.

THANKS

I thought the purpose of a larger second ring gap was to keep from trying to lift the top ring off the ring land during compression? I've always been told to run a larger second gap (8-10% bigger than top gap) for this very reason. What's the cylinder pressure on one of these engines? Maybe it's low enough that you don't have this problem. Have you torn down/inspected any of the engines you have in service using this type of ring gap? I'm curious what the ring lands/cylinder walls look like. Will that .013 second gap need to be changed with the addition of a blower?

Where do you find a Blue Racer roller cam?

Interesting!

??:confused:
The only way to tell if the quench or rings did not make a difference would be to correct them and dyno the same engine again,...right?
How can you compare scenario A to scenario B when you only tested one of them?
I am missing something here.

??:confused:
The only way to tell if the quench or rings did not make a difference would be to correct them and dyno the same engine again,...right?
How can you compare scenario A to scenario B when you only tested one of them?
I am missing something here.

That is my thought also. Also, the ring end gap clearance cold is to compensate for ring expansion during combustion tempuratures to prevent the end gaps from butting together.

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Mat

Where do you find a Blue Racer roller cam?
At AutoZone or Advance auto parts........yuk, yuk.......

You guys are funny! :D :D Some people just ask for it I guess. :)

I was also wondering the same thing. I cant tell you how you can compare the results of two different buildups when you only build one. Sure, the numbers look good, but who is to say how much more(or possibly less) successful the whole effort could have been with adjustments to ring gaps and quench without actually comparing the results in both situations. I cant?

I, too, am missing the point. Sounds like the Steven Jobs syndrome: We just threw these parts together, casting conventional wisdom aside, and proved that all the great engine builders don't know what they are talking about. No cam figures, no flow numbers, no atmospheric conditions: but a great, off-the-shelf combo; with a "little head work" thrown in for free. A blower on 11 to 1 with bad quench. That does fly in the face of the manufactures. Hard to believe they made all those reverse deflectors for nothing. Also, I would not call .018" gap tight. A good round hole and a forged piston can get by with that at lower HP levels. But when you put a blower on that and double the heat, you may wish you didn't give a guarantee with that block. Just my opinion.

Get a machinery handbook and look up the expansion rate for your ring material. Do the math and see how much heat you need to butt the gap. I think you will be surprised at how little leeway you have. My figures say your rings will butt when the ring temperature reaches 300 degrees F. When that piston head is 450 degrees, it will be putting a lot of heat into that ring. Of course, the block is going to expand at the same rate as the ring, but it won't get anywhere near as hot as the rings.

I wonder how much hp this motor would have made on a more conservative/west coast dyno;), those are big block numbers from a nothing special smallblock.
P.S. I find those numbers very hard to believe.

I wonder how much hp this motor would have made on a more conservative/west coast dyno;), those are big block numbers from a nothing special smallblock.
P.S. I find those numbers very hard to believe.

Hi Bob, we're over on the east coast wondering why more people can't get higher numbers from their combo's. Our dyno (a Stuska/Depac) is fairly conservative. A year back Scott (Schafiroff) got 686 HP (he uses a "Superflow" however) from a 472" SB (N/A-93 octane) using 23 degree heads, a few months later we got 732+ HP from a 468" SB (N/A-93 octane also) without too much trouble AND on the first "shot". Another item while I'm here, the numbers we give out you can usually add a few extra HP to, as we get to do some add'l testing on the units before they leave the dyno room. The 468" above actually made more than the 732, but was delivered at that number. It comes down to a system of "checks and balances". We have the ability to build the unit, dyno it, and run it at the track (in pro-cars, not
"door-slammers"), thereby confirming ALL the numbers we've put together. Believe it or not, it all starts at the flow-bench, once the heads are off the
bench we know how much power is available with the rest of the "right" components. These HP numbers are (fairly) easy for us. I'll just add one more important item here, there is probably about a half-dozen (real) head porters in the country, we happen to be fortunate enough to have one of these people in our "circle". He laid out the platform for the 468" SB. The intake, heads, and cam are the "key" items in ALL these units. Thanks, Gary in N.Y.
P.S. EVERY individual one we build has it's own requirements, this is very important to keep in mind. The reason I say this is because the "quench" area on the 406" in this post wasn't critical, however it was an "extremely" important dimension in that 468" unit above. The 468" runs only on 89 octane when street-driven and only on 93 octane when "raced". There's no fuel mixing in that unit, and is able to 9.0's on "muscle". Gas it up at the local station and go racin'.

At 10.8:1 with a decent sized roller cam this engine is nowhere close to detonation. As a result it does fine with a far-from-ideal quench setup.

I think it would pick up power and be LESS PRONE detonation with a .035-.040" quench. Might even break 600 HP.

PS. Sorry to sound critical, but I would never consider for a second putting a nylon gear timing set in a performance motor. They didn't last in stock 70's 350's . . . why use one to "pull" a roller valvetrain when you can get a cheap double roller set for $25?

No A to B comparison......??? I know a dyno operator that can make a dyno say anything you want. Apply 8lbs of boost to that time bomb with 100 octane fuel and you can expect no less than lifted ring lands...god forbid he try's N20. been there done that

At 10.8:1 with a decent sized roller cam this engine is nowhere close to detonation. As a result it does fine with a far-from-ideal quench setup.

I think it would pick up power and be LESS PRONE detonation with a .035-.040" quench. Might even break 600 HP.

PS. Sorry to sound critical, but I would never consider for a second putting a nylon gear timing set in a performance motor. They didn't last in stock 70's 350's . . . why use one to "pull" a roller valvetrain when you can get a cheap double roller set for $25?

We know there are a high number of "savvy" people up here, and that's good. Let me expand a little more about this unit. From "day-one" it was contracted to be built on a "blown" platform, a BDS unit to be exact. Customer made last minute decision to use it temporarily on N/A (carbureted) platform. We changed the cam and delivered the unit. We already have a fresh deposit for it's return in about 6-8 months to be changed back the original plan. We actually have the cam here for the blower for months now. When it comes back it will only get the cam change and NOTHING else, not pistons, rings, head gaskets, nothing. The ring gaps will remain as they are. From previously testing "hundreds" and more possibly "thousands" of units (over the years) we have no concern about failure here. As for the "nylon" gear, it's in there for very specific reasons, it "saves" roller lifters, and by the way, it takes a lot less "pressure" to turn this unit over, than anything with a "flat-tappet" setup. The cam specs are 256/264 @ .050, .668" intake lift, .613" exhaust lift, and a 106 L/S installed "straight-up". The part number for the cam is WG5008MR, a Blue-Racer grind along with a set of WG450-16 roller lifters, also the Blue-Racer series. This unit is not a big secret with us, so I have no problem releasing specs or part numbers. The heads came off the bench with 300+ CFM on the 4.155" bore. We did spend a little more time than "normal" on the exhaust side due to the blower at the later date. I don't have the
"flow chart" here at the moment. It MAY possibly get a Comp Cams "belt-drive" when it comes back, but that's undecided as of today. Thanks, Gary in N.Y.
P.S. Some units we can release specs for, however, the one's on the
"cutting-edge" stay under wraps. We just got a visit from a customer (Tommy @ Super-Pro Performance), that we built a 350" SB in a '62 Vette using a solid roller, runs 10.3'/10.4's, street-driven (a nice weather car), and was done in 1990. Still runs fine with a number of spring changes over the years, same roller lifters inside. In our area (Long Island) he's a well known chassis builder.

ERIC68,

Bill Jenkins championed the nylon sprocket to keep the crank from rattleing the cam. I believe a timing belt drive is better and more reliable. The Grump used what he had at the time to achieve his goal. We have better stuff now. Jenkins also went fast with heads we now throw in the dumpster. When you use yesterdays parts, you get yesterdays HP. Smokey thought gear drives were best, and for Smokey, they were. He was running flat lifters with little spring pressure. I don't think that would be the best thing for a 9500 RPM roller cam setup even though it can be done. (I always thought there should be a harmonic damper on the rear of the cam. Can't believe no one has made one yet. Or a second belt drive at the rear of the cam to help negate cam twist.)

Interesting on the nylon cam gear . . . sorry to be disagreeable but I just can't see a nylon gear saving roller lifters, making more power, or doing anything other than coming apart in a race motor. My motor and many others seem to do fine with double roller sets and SR lifters. Good point Kirk about yesterdays parts on yesterdays motors.

I'm not big on magazine dyno tests, but every now and then there is an interesting one. There was one recently (sorry forgot what mag and issue) that tested the good old double roller vs. gear drive vs. belt and suprisingly there was not enough difference to tell them apart. As I recall the gear drive actually made the most HP, but it was a minimal spread and within the tolerance for error IMO. I expected the belt setup to win, but it did not.

With 256 @ .050 and 10.8 static I think you could run any quench you want to without detonation. I gaurantee more power with a tighter quench (try .035") and more power on the same gas. I run 11.3:1 with a 248*, 108* LSA, 104* ICL SR cam in my 383 and had no detonation on 93 octane gas. Have actually run 91 in it and had no problems when driving easy (never had the guts to get on it with the midgrade)

To each his own I suppose . . .