USRA Iron Man B Mod Build

[Retiredracer]

Hey guys,
Retiredracer coming out of retirement so to say. I'm getting set to begin building a new USRA B-Mod for competition later this year. Around 10 years ago I was running a similar class, and had a pretty solid engine combo. Things have changed since then.

Must be stock appearing. Any American make is permitted. Absolutely no changes allowed. Must use
stock firing order for that make and model (GM to GM, Ford to Ford, etc.). Titanium is not allowed.
16.7.2 May be a maximum of 360 cubic inches. (370 c.i. for Chrysler).
16.7.3 Must be a maximum 9.5:1 compression. Exception: 302-, 305-, 307- and 318-cubic-inch engines may run
10.5:1 compression. Only flat top or dished pistons are permitted.
16.7.4 Must appear strictly stock for that model and make and in the original mounts. Parts for 400 cubic inches
or larger are not allowed. Stroke must match block. Block casting number must remain visible.
16.7.5 Only stock appearing crankshafts are permitted. Lightweight cranks are not allowed. No undercut, bull
nosed, gun drilled or knife edge crankshafts allowed.
16.7.6 Lightweight, aluminum and/or fluid dampeners are not allowed
16.7.7 GM five and seven-tenths (5.7) inch or six (6) inch rods are permitted. Must be stock appearing I-beam
non-polished rod. Aluminum or light weight is not allowed. Cap screw rods are permitted
16.7.8 A minimum one (1) inch plug above the oil level in the side of the oil pan is recommended. If not utilizing
a plug, oil pan will have to be removed at time of inspection.
16.7.9 Only stock, unaltered two-barrel low rise cast iron intake manifolds or Approved aluminum intakes are
permitted. Approved aluminum intakes are GM - Edelbrock (#2101 or #2701) or Weiand (#7547 or
#7547-1); Ford - Edelbrock (#2121 or #2181 or #2665) or Weiand (#7515 or #8023 or #7516);
Chrysler – Edelbrock (#2176) or Weiand (#7545 or #8022). Porting, polishing or port machining is not
allowed. Bowtie, aftermarket, SVO and W2, marine, VORTEC or other special production intake manifolds
are not allowed. External cooler lines from back of intake to front of intake is permitted.
16.7.10 Cast iron stock production or aftermarket steel stock replacement heads are permitted. Porting and/or
polishing is not allowed. GM cars must utilize 76cc heads (approved head numbers are 336, 339, 388,
441, 454, 487, 624, 813, 882, 991 and 993). Aftermarket head numbers are: GM – EQ Part #CC167ES2
or #CH350I; Dart Part #10024267 or #10024360; World Products Part #043600 or #042670; Ford
– World Products Part #53030; Chrysler – EQ Part #CH138B; RHS/Indy Part #20300 or #20301. Heads
may be flat milled to reach the 9.5:1 compression rule. Valve size no larger than 2.02 intake and 1.60
exhaust. VORTEC heads are not allowed. Beehive valve springs are not allowed.
16.7.11 Screw-in studs, guide plates and poly-locks are permitted.
16.7.12 Roller cams and lifters are not allowed. Roller Rocker arms are not allowed (stock-type stamped steel
rocker arms or cast steel rocker arms only). Roller tip rocker arms are permitted. Chryslers may utilize
OEM steel shaft rockers but may not exceed one hundred twenty (120) pounds of valve spring seat
pressure and must maintain OEM valve spring dimensions. Under valve cover pressurized valve train
oiling systems are not allowed.
16.7.13 Mushroom lifters are not allowed (stock diameter only). Must match make and model.


That would be our rules. They have included a Concept engine, along the same lines, but with a hydraulic camshaft, only one head choice and a 6200 RPM limit, a 2600 Pound weight rule, and a 4 barrel carb. I'd prefer to stay on the 2 barrel with E-85 or Race fuel.

I'd like your opinions. I have an idea of which way I want to go. I'm unsure on valve train parts, as in Valves, Retainers etc. I know we will probably run PAC 1201 Springs. Not sure if OEM Head with the bigger valves, or the EQ/World Head will be better.

Thanks in advance

[NormS]

As far as power is concerned, I think the Edelbrock 4 barrel intake with a 4 barrel carb would be the best choice. If you are limited to a narrow hard tire, and think that traction could be a problem, you could use a vacuum secondary 4 barrel to soften the throttle response. With the right mods to the vacuum secondary system, the vacuum sec carb would make the same power as an equal sized double pumper. A factory 2 barrel intake , like the one used on the 400 small block back in the '70's, would have a limiting effect on your power, and might not have good enough distribution with E85 or any other alcohol based fuel, even though it does have decent distribution with gas.
With 9.5:1 compression, you probably won't need a racing gas, at most a blend of 93 octane pump gas and some racing gas.With the limited breathing ability of an engine like this and a relatively low CR, it's easy to give the fuel too much octane, and too slow a burn rate. Keep in mind that the percentage of ethanol in E85 varies with the season, so you might need to chase the carb calibration to keep up with that inconsistency.

[Rosenbluth]

I'd look at some thin piston rings, metric 1.5 or the .043 ring packs. I'm sure other pistons brands have them, but Mahle and Diamond always comes to my mind. I always wanted to try the Eagle ESP Armor coating, they say it's worth some HP. I'd try and go low drag best you can. I'd get the hollow stem Ferrea valves for the heads. Lighter is faster. Get a super nice valve job on them and maximize as much flow as you can. Get a custom cam to match everything, call Mike Jones or Chris Straub, so you dont' miss the mark on the cam. If you wanna spend some money and push the edge, get some Brezinksi heads and intakes that are acid ported..www.castheads.com...still looks like cast when they are done so you won't get caught. I've run em, been teched and teched again, and never a word about them.
Like NormS stated, careful with the racefuel and the lower compression, could make it a little lazy if you run too much octane with lower compression.
On these restriced motor builds, I liked to low drag as much of the car as possible. I got the ring and pinion of the rear end REM coated (it's like chrome), I even took the trans gears that were engaged in high gear and had them REM coated. Used a synthetic lube in both rear end and trans. I even had the carrier bearings in the rearend polished, along with the bearings in all the wheel hubs. Make sure your brakes aren't draggin, could even have ur rotors turned so they are a bit waved, that way it kicks the pads off the rotors on the first revolution after you let off the brake pedal...these things aren't all that expensive, but they do add up to some hp improvement, trust me. I sometimes would just take a few minutes to sit and study my car, thinking about how to reduce drag and friction. Things will come to mind, if you think about it long and hard enough. Good luck to you.

[NormS]

The key to short track racing is corner speed and maintaining traction.Years ago in Arizona, there was an oval track class running at the local 3/8 mile track. I had dynoed most of the engines in the field, and the difference from strongest to weakest was 40 HP/ 30 ft-lbs. The car with the weakest engine was run by a 16 year old kid,and his dad, on a very restricted budget. The kid was VERY smooth, and the dad really knew how to set up the chassis for good corner speed. The result is a race car that made most of the more powerful cars look like they were dragging anchors. Because his corner speed was better than all the rest, he came out of the corners with more speed, and because of that, carried more speed down the straights, even with less HP. He rarely lost traction, so the car was hooked up all the time, putting all the power that the engine had to the track. The other racers complained that he must be cheating,that his engine must be illegal, because he was blowing their doors off race after race. His car was one of the few totally legal cars in the field.
So work on getting the car to handle in the corners, and not lose traction coming out of the corners. Find the fastest line around the track, and try to hit it every lap, except when you are passing other cars ( the ones that are blazing their tires, or using the entire width of the track due to poor handling).Smooth is fast. Fast is smooth.

[Retiredracer]

Thanks guys,

I'm not new to the racing deal, I just haven't been doing the driving full time lately, and with the "crate" engine coming around, the thought of engine builds haven't been there. I planned on utilizing a thin ring pack piston. As far as REM polishing, that is illegal in some areas, some not. I have ran REM polished R&P in my quick change before. Hollow stem valves also are not legal. Brezenski, they've got a CC for the runners and will pull the head and CC it. We had a set of 441 done by them and intake that we ran on a motor for a while, and although we never got "busted", we were on to and thus sold the heads off. Corner speed is key, and I feel the package I run on cars I'm paid to work with is top notch, many wins over the last 4 years. With the rules specifying a cast rotating assembly, what will be my best choice. For the record, I've been racing since I quit this class, in the A modified class, and stock car class, but they are all different animals and I've been lucky enough to not have to make these decisions on those cars. This will be all my own equipment.

My main questions are:
Am I going to give up power by going with an OEM Head, valve sizes opened up to 2.02/1.6 vs the EQ CH350 Head?
What will the best valves be to use, regardless of head choice
Is it worth going to E-85 with the inconsistencies in the fuel. A sponsor will buy barrels of whatever fuel we need.
Is there anything to be gained by going with lightweight lifters?
What will be the best choice for retainers and locks?
Is a standard High Volume Oil pump still sufficient? I want to say the last modified motor I built, I put the better pump on, with the 3/4" tube, High volume High Pressure etc. M155-HV Do I need the 10555 Melling? Remember we're maybe making 420 horse give or take, and turning 7200 Maximum.

Thanks guys
Larry

[englertracing]

351C

[englertracing]

look at total seals new "ultra thin rings"
.9 .9 1.5

I second the cast heads thing as well

[Ks Fats]

Something to think about: I believe that USRA requires a gauge legal 4412. If that is true then setting it up for E-85 will reduce the overall c.f.m. of the carb due to the extra volume of fuel required in each circuit. E-85 and methanol are both "do-able" but they are most effective when you can do booster changes, baseplate modification and venturi work to enhance flow. Might be better off with race gas.

[Krooser]

First find out what the fast cars are running...just as a reference.

Valve train.....best you can afford. Pac springs are good...we've liked Kmotion too.

Pistons...Wiseco, Mahle, Ractec or Manley all seem to be good. Low friction ring pack. Light pins if in the budget.

Rods? Anything but Eagle...lots of guys run stock GM powdered metal with success...my motor guy hates em but my kid has them in his Wissota b mod.

Heads...EQ seem to work good.

Cam...Jones, Bullet, Camcraft or Chris Straub can help... Howard's is good too.

A stock Melling pump should work.

Willy's makes a good carb... My son's is gauge legal.

You need a good oil pan...Champ is my suggestion.

The Edelbrock intake is good.

[phantomfab]

lightweight valves are your friend, seems easier to control the light valve with a spring that doesnt destroy the stamped rocker arms in the long run, we also run aluminum retainers cause they are cheaper but they require checking cause they do give problems some times. I've personally never had a problem but just heard horror stories of them coming apart. I run a custom grind cam from crane and my brother runs an isky. We also had a cheap summit circle track cam, a ct101 i believe. cars ran with a tenth of each other on a test and tune on two different weekends. more to that story though.

intake. run the 2701 guys on here recommend that to me.

heads, EQ's are the easy route. Run a 487 if you can find it. 993's run good from people i know. My machinist dynoed an old crate motor with dish pistons and the stock 624's with a 2701 intake and headers, running on 91 with a two barrel made 330ish hp with an unknown cam.

My bmod has stock rods PM rods with good bolts and hyp flattops just cheap h345dc pistons, all three motors for our bomds have them, theyre heavier than most but we've never had a piston failure and theyre less than $100 a set.

i run a stock 442 crank, my brother runs a steel gm crank, we both turn 7200 every weekend, his motor has been doing it for two seasons just with a freshen at half season. he runs stock rods.

Runnign e-85 with the two barrel around my area is whats outfront. I buy 5 gallons of e98 and then get my e85 from which is usually around e75 in my area and mix the e98 til it measures a true 83 percent E so i can still give a litle room to pass tech.

A big advantage in this class is trying to find things that will get rid of parasitic loss. heavy rotating assemblies are a parasitic loss but i live with it for the cost. Running e85 will help keep the engine cool so one option is find a smaller fan that doesnt have a lot of pitch. ditch the flex fans, they eat horsepower like cray. Look up on youtube engine masters, and the episode they do on fans. The engine they use is a 602 crate, the results will surprise you. That made my buddy with the dyno do some research of his own and he saw losses of up to 35 hp. from just the fan. Also, while i was on a budget at the beginning of the season i ran a th350 that was stock with the heavy ass converter. Last weekend i put in a power glide with a coupler and picked up 2 tenths on my laptime average. enough to go from around 10-6 every week to running 3rd last weekend after winning my heat. I did change some other things on the car that made a huge weekend the weekend before but the transmission was a killer when the track was fast. On dryslick the heavy torque converter did slow it down some to make it hook harder it seemed, but a good driver will compensate. This is my first season of actually driving my own car so it helped me alot on a slick track, but the glide made me much faster on a tacky track. If alot of guys run crate engines near you like they do at a track near me, find out what they run for a gear and make yours lower. make it where at the rev limiter youre going the same speed you have a 1000 rpm advantage . So many old timers told me to make it match where i made peek power but i found i can eat a crate alive if i gear it to crank the extra 1k rpm. But an engine failure doesnt scare me i have a fresh engine on the stand. If you dont feel comfortable rding he rev limiter than dont. But if the crates arent riding the rev limiter then you wont be either most likely, if you are you're going faster.

Good luck on the build.

[Retiredracer]

Has anyone flowed back to back the EQ head and then a 441/487 Head with the big valves?