need help putting a bracket SBC combo together

[ProStreet68SB]

so i've decided that i'd like to put together a nice bracket motor than will have plenty of street duty also, i'll give my thoughts on what i have so far, bare in mind i havent bought anything but my block so far so things can be made to work. i'd like it to run on pump gas (91)
My block is a 350 2-bolt main block
4-bolt splayed mains ( whats good and whats not in this area?)
eagle forged stroker rotating assembly with h-beam rods and flat tops ( the rebuild kit that is)
I'd like to get a set of Trick Flow heads, was looking at their 75cc heads (def open to suggestions though)
Cam- yet to be determined maybe you guys can help me out here.( would like a solid roller since it's a bracket motor)
intake- still havent figured it out
carb- like to run a quadra jet just to be a little different, but want it to work with nitrous too.
and last but not least, nitrous, i want to be able to run a 200shot of nitrous, but from ZEXs website i cant run that without running race gas, why is that?
if i'm missing anything let me know, or any suggestions i'm very open and willing to learn person, looking for about 425-475 before nitrous and i'll be happy. sorry for the long post.

Thanks,
Nick

[PanelDeland]

I would look at the calculations and see if the 75 cc heads are going to give you the compression ratio for 91.Depending on your combo you may need to run a higher octane to prevent pinging if your CR is high.
The reason they want you to run race fuel with nitrous is that NOX is an oxidizer.It increases the available oxegen for the engine to run.In order to do that you must also have more fuel.You will also build more cylinder pressure and need the higher octane to prevent pinging.
Keep in mind that "if" you use a 400 block and stroke it you will only need a little over 1 hp per ci to reach the 425-475 hp goal thus requiring a slightly milder combo which would make the street driven goal easier while still giving you the power for bracket work.
The 383 will need to produce about 1.25 -1.5 hp per ci to reach the same goal.Just throwing some things out there for consideration.

[Marv D]

Nick, I'll just give you my thoughts,, there are a thousand ways to skin this cat. First thing you HAVE to realize,, faster and quicker doesn't win a bracket race. CONSISTANCY in performance and driver is what wins there. But we'll leave that for another day.

As far as the splayed mains,, don't waste your time and $'s. By the time a set of poorly made Chineese splayed main caps are fitted to a block,, you looking at over $300,, more like $400 and maybe even $500 (including the cpas that is). It is a lot of work to make a poorly machined set of splayed main caps fit a block. I'd highly suggest you just skip that idea all together. Yes, a 4bolt main block will toplerate more abuse than a 2bolt,,, but when was the last time you heard of a 2bolt block exploding because there wasn't enough bolts in the main caps to keep the crank in place???? More often than not the rods give way on the SBC LONG before the main caps. So puting splayed mains on a 2bolt block at this level is a bandaide over a mosquitoe bite,, kind-of overkill. To be sure here,,,, I'm not saying it's a 'bad' idea, just that at the splayed main deal is not what "I" would spend my money on here. You should seek out Carl at cncblocksne and talk with him about GM production blocks. He is the first to say that the GM sbc castings were never intended for anything over 370HP. Remember that,,, the height of the muscle car era the LT-hot-dawg of the era made 370HP at 11:1 compression and using the 'then' street available ~100~ octane fuel. Point I'm getting at is even the GM 4bolt castings of the era were never intended for 400 or 450HP. Adding splayed mains doesn't do crap for making the block strong. If you want something intended for 500+HP your looking at something other than a production block,, Bowtie, Rocket blocks, World, Dart,, and... Dart has their new SHP sportsman block at around $1200, or a well prepped Motown / Dart will get more into the $2000 to $2500 range just depending on bells and whistles you have them do. I can tell you first hand that if you add splayed mains to a GM production casting, do a short fill to help rigidity in the cylinder walls, deck, clearance, bore hone,, get it ready for assembly, you will be over $1200, NO BOUBT ABOUT IT!!!

OK, you know your options there,, let's drop back to square one. You have a GM block,,, I would not spend ONE PENNY on anything based around that block till it has been to the machine shop, baked clean, checked for cracks and SONIC CHECKED FOR CYLINDER WALL THICKNESS!!! The production castings are notorious for shift and thin cylinder walls are a POOR platform for a performance build. Don't go there, spend the $'s and KNOW where your starting from. You'll probably spend $100 to $150 just having the casting baked, jet washed, cam bearings / frost plugs knocked out, magnifluxed, and walls sonic checked. And you may just find your looking for a new block anyways!

OK, once you've done the deed and have a good servicable block (GM, aftermarket, or whatever) You need to decide cubic inches. And believe me, SIZE DOES MATTER! If your starting from scratch (not using your existing crank and pistons, etc) there is no rationality in the world to stick with a 350. If your buying a crank, your buying pistons,, your a part number and a little clearancing away from a 383.

302's, 327's are only used in racing any more because of some class rules, The 350 is quickly falling into that same catagory. It's so easy and cheap to build a 383,, there is no reason to throw torque out the window with a 350 build. Go for the big strokes,, you won't be disappointed. Cost is the same. Only addition is some block clearancing which you can do, or your machinist will rough clearance the block for about $60 - $100. Or if your using one of the aftermarket blocks,, there is no clearancing, just bolt everything together.

Torque accelerates the car down the track to ET's. HP is nothing but a function of torque and time. Build for the most AVERAGE torque within the parts you have, and you'll have the quickest, and the most consistant bracket car. Here were back to 'TORQUE' and STROKE. Easiest way to build more torque out of your 350 block, is to add stroke. There isn't enough room to make the bore significantly larger, so stroke is the only alternative. Lot's of guys today are going the extra step (or should I say 1/8") to a 3.875" stroke for a 396 sbc. That's a lot of work and those parts are not nearly as 'shelf stock' as the 383. Besides,, the 383 combinations have been out there for decades. There are plenty of tried and true combinations.

So to this point where whould "I" be?? If that 2bolt block didn't check out near perfect, I'd either find a good servicable used 4bolt block, or order one of the new Dart SHP $1200 blocks. Let your budget be your guide there. And 'I' would already have decided on a 383 vs any 350 build.

Rotating assembly.... Eagle has apparently resolved the QC issues of a few years ago. They had a horrible reputation for journals being off size and in general a second rate item. I have 2 Eagle cranks that are PROOF positive of the horrible finish quality, so it's not just rumor. Just a litle tidbit as I have come to understand it... Eagle and Scat are made in the same foundary in China. Eagle is finished and boxed there, Scat has their cranks shipped in rough cut / semi-finished form to the US, where they are finish machined by US machinists. THAT alone is reason enough to buy Scat over Eagle in my book. And before you get hung up on names... Scat makes a large line of low end cranks, but they also make a EXTREMELY fine line of upper end cranks also. I'm running a 4" stroke Scat ultra light (that's a $1200 crankshaft) in my 800HP sbc bracket motor. I'm 0.25 seconds from running SuperComp (8.90) numbers NORMALLY ASPIRATED in a all steel door car. NEVER underestimate / over estimate the quality of a line of parts bust because they are popular in one 'budget' of components. Look at the whole line they offer, not just what the car rage / boards and Slummit and Jeggie offer on the front page.

There are a lot of companies out there right now offering very decent prices on stroker packages. The norm is: Eagle 4340 crank, Eagle ESP H-beam 6" stroker rods, and JE/SRP pistons. Nothing wrong with that package IMO. Just be aware that this is not a balanced assembly, your in for about $200 for balancing after you get ALL the parts together. (including balancer, flex plate, rings, and bearings) Also most of those packages are a deal because they are a 'popular' package,,, the manufacturers have a large production run of one part. i.e. the JE pistons with most of the packages are a 0.25" dome and 12:1 compression with a 64cc head.
Also some of the packages come with bearings and rings, some don't. KNOW what your getting and not getting with the package you order.

So where are we. Block, and rotator assembly. But to do that, you HAVE to know EXACTLY what cylinder head and what cubic inch motor were building,,, No other way can you order pistons and know what the resulting compression ratio we'll end up with. Brings us full circle and were not going to order one part till we know where were going with block, and cubic inches. You can't do ANYTHING till you know 100% for sure what you have. A motor, bracket or street or all out heads up motor is a combination of specs and components, not brand names.

So let's assume you've ran the gauntlet and have block and cubic inch decided. Your first REAL decision is budget for the heads. Power is made in the heads,,,, all the trick cranks, rods, cool rockers and cams,, not one of those items are as important as the heads in determining the resulting power output. I always advise guys to pick a budget for the motor,, and AT LEAST 1/3 of that is for the heads. A good set of street/strip heads will be into your budget around $1500 minimum, to $2500 for upper end STREET duty heads. Believe me, you can dump $6000 into a set of full tilt race heads in a heartbeat. If you want to make BIG numbers, you have to play with the big budgets unfortunately. Don't play the game of advertised flow numbers. There all a farce. The only advertised numbers I've seen that are 'realistic' when the heads go across a reputable flow bence are AFR's,, Brodies are always real close too. Even their heads can be off, but AFR will guarentee their heads to flow +/- 2% of advertised. I myself am not in the slightest impressed with the TrickFlow line. Especially their old twisted wedge crap, STAY away from that!!! The new generation TFS head is a near clone of the Bowtie Phase 6 head from everything I have been able to find on them. Nice head, but there is better out there for the $'s. There 18 degree stuff is pretty cool, but, you better have a BIG budget to go that route (special intake, headers and all). And while were on the subect of heads,, if your staying under 360 cubic inches,, stick with a head that has a port in the 200-210cc range. If your going 383-406, 210-220cc(max), and if your going for the gusto,,, a 434sbc will tolerate everything you can throw at it. The raised runner 227+ heads and up is all I'd consider for a bracket 434. Brodix's new 235cc cnc head is a nice piece for a big inch sbc, but WAY overboard for anything on the street and less than 410" IMO. so choose your heads wisely. I'm not going to bash the TFS line, just suggest you look at all the alternatives before you choose. And don't let name or price drive your decision,,, let the COMBINATION dictate what it needs.

Not even going to get in to cam. Just to say,, on the street you surely don't need a solid roller. I'd STRONGLY suggest you consider a hydraulic roller. It will limit rpm's to a big degree, but is reliable and can deliver nearly as agressive of valve action as a solid roller,,, without the maintenance or noise. But you can't even think about cam before the rest of the combination is cast in stone (cubic inches, heads, compression etc)

That enough for now??? have the block checked, decide on a budget for the heads. THEN things can go forward

[hotrod 80]

Marv has led you in a very good direction . I'll just add that spraying pump gas is very trick and your tune up needs to be spot on and properly flowed over your elapsed time . You wil also IMO have consistancy problems with and edgy tuneup . The race fuel is a safety net . No need for spray in the bracket race world . Index racing maybe .

[ProStreet68SB]

thanks for the advice guys to answer a few questions so you guys can hopefully help me some more.

I've grown up around bracket racing and do test and tune atleast once every other week at my local 1/8th mile strip, and nitrous wouldnt be there to run for consistency just for fun when i wanna use at the strip, other than yes no nitrous for racing, i already have my block and it's already be cleaned and magnafluxed and it checked good(never been bored over, when disassembled it had less than 100k miles on it). I'm looking at the 383 rotating assembly and rebuild kit from eagle, that has the 3d forged rods(6in rods), mahle flattop pistons, clevites bearings and what not. Head wise, i was recommended the AFR 195 Elminators and they're about $1400 for a complete head, the only thing i'd have done is the springs changed to what ever i get cam wise. about stock blocks, my engine builders currently runs a destroked 302 chevy on a stock that according to him makes 650hp, he has 18k in his top end alone, oh yeah and iron heads, he's held several NHRA records over the years, so i have no doubt in his ability to put my motor together correctly. I prolly forgetting a couple of things but if i did, let me know

thanks so far,
Nick

*edit* and i'm going with a solid roller, because it is going to be a bracket motor and solid is going to be over all more consistent than a hydraulic.

[Marv D]

I'd really like to get you in touch with Jay Allen or LSM cams about the hydraulic roller. Jay and I worked through a scenario with a Morel hydraulic roller where you give the plunger ONLY 0.015" of preload,, same as a tight lash solid. You keep HEAVY springs and the valve action on one of his Hyd Roller cams is just as agressive as a solid. True the hydraulic roller is heavy, with the full mechanics of a solid roller and the full mechanics of a hydraulic lifter, and then add the oil. LOTS of weight and in a retro-fit application with link baars and all you have a pretty massive lifter. Your options are to run a hydra-rev package like AFR sells for their heads which is some, but limited help, or limit rpm's whick is counterproductive to making power with a smaller motor like this,,,,,,, or Jays scenario.
The last build for my truck I chose to use the AFR Hydra-Rev kit on the 383 in there now. Never again. I can do much better with the custom cam from Jay and heavier springs. Right now I can get 6600rpm OK, and it starts to fall off and ET deteriorates if I spin it 6800 or above. The Crane hydraulic roller cam I have now really isn't intended to make power up there anyways so valve/lifter bounce is just abuse for the sake of RPM.

Anyways, where I'm going is I'd have to respectuflly disagree with the thought of a hydraulic roller not being just as, if not more consistant than a solid roller at this level. But,,, again that's just my opinion and experience with them. I can show you a fistfull if 12.x second ET slips with the truck where the ET varies less through the day than the solid roller motor in the Nova. Two different animals for sure, but consistancy is consistancy.