impaled

i am thinking at the moment of building a 377 (for those who dont know, its a 400 block destroked w/ the 350 crank and slightly overbored).

the reason i am thinking 377 is because my goal for this engine is to get it to safely rev past 7500 with no blower, but with some nitrous. this is going to be a strip car, but still be able to drive her there. as far as power goes, i would like to see around 600 at the rear wheels without the juice. i am not going to get into components in this post, but i dont think that will be an issue.

the reason why i would like some opinion when it comes to using a 400 block is because they have thinner cylinder walls and was wondering how it would hold up on some spray (a 150 shot to start)...

or, should i scrap that and go with a 355 or 383 and change my goals a little bit?

Sonix

iTrader: (1)

Do a search on "destroked 400" or "377" and you'll quickly see why this is a bad idea.
Giving up cubes is like burning money for the fun of being different.
The stroke isn't what limits your RPM right now, it's not a diesel. It's the valvetrain.
Upgrade that with all your money, as well as the rotating assembly, and keep it a 406cid engine and you'll be laughing.

impaled

the engine will have a fully competent valve train, so that wont be the issue. it is definitely a debatable topic (thats why i am asking... lol), but i would still think that the shorter stroke would help it spin up even higher with less stress on everything.

Sonix

iTrader: (1)

You'd think so, but no.
Only above 10,000RPM is that even a perceptible factor.
Many members on here (and elsewhere) run a stroked 350 (383) or stroked 400 (434) to extremely high RPM's. only one or two members have, or have used destroked 400's. They liked them, but who's to say the car wouldn't have been faster had they went the other way with the crank stroke?

Very debatable though.
But a large bore small stroke engine will be more detonation prone then a small bore, long stroke engine.

Just as a fun exercise, why don't you look up the bore-x-stroke of the famed LS1 engine and the fabled LS6 and LS7 engines?

tpi user

ya but ithink he is lookin for a really serious strip car that can still be a little streetworthy. it looks like hes lookin 4 an rpm range of 4500-8500,correct me if im wrong impaled. and imo a 3.750 stroke is gonna need a goin thru often with those piston speeds alot of weight bein thrown around at 8000 rpm in that lower end. now you say ur gonna have a good valetrain right? you better lol cause your not talkin parts out of summit racin. but hey if your serious go for it just ask the nascar boys why their builden 358 cu in. by the way their runnin a 4.185 bore an a 3.25 stroke for 700 or 800 miles at hangin rpms of 8500- 9500. they could make em last alot longer than that , but there their to win.

Sonix

iTrader: (1)

Ok, then lets break down the use-budget for this car then.
Don't build it to hit xyz RPM, that's silly. Higher RPM is ALWAYS the death of an engine. Besides, RPM isn't as important as 1/4 mile time or trap speed right? I mean would you rather be in the 350 chevy turning 6000RPM and WINNING, or the honda pulling 7500RPM and LOSING. (PS RPM doesn't matter much to me )
I'm just yanking on ya, but you get my point eh? Don't put on the horse blinders and only look at RPM, focus on going the fastest, and that's not always the highest RPM.

What type of fuel do you want to run? Do you EVER want to drive it on the street, or are we talking about trailering it to the track?

Ask Ross what he thinks of this idea. He's the first guy to come to mind who's done that engine combo. I think he had a 380 that was FAST FAST FAST. Now he has a 434 and it's FASTER. (Think about it being the same block, but longer stroke...) I think in his case he didn't re-use the block, but technically speaking, it could have been....

Just food for thought.

Good to know TPI user, I never knew how the nascar guys came up with 358cid. That's a very oddball bore/stroke setup, but hey, I can't argue with them now can I ?

Orr89RocZ

iTrader: (20)

i think spin up and rev ability is more related to piston/rod weight than length of the stroke

farther the piston travels up and down the bore, and the faster it goes, the more forces are acting on the rod. BUT those inertia forces are based on weight of the piston and rod, so if you reduce those masses, there will be less net forces acting on the rod as rpms go up even tho piston speed is greatly increased over shorter stroker/shorter rod setups.

Now thats where it could mean smaller strokes and shorter rods motors can rev higher than the other type motors, since their internals may be lighter than the longer rods/stroker motors and thus can safely rev higher since the stress/forces are lower. but there are some short rod/small stroke cranks that are still heavy and wont rev without breaking

That being said i'd go with cubes when you can get them and get the BEST strongest lightest rotating assembly you can get. lightweight pistons, rods, and cranks with the knife-edged counterweights to reduce drag from oil and such

7500rpm motor is pricey but can be done.

tpi user

hey i agree with you both but he sounded like he wanted it to an money was no object i wasnt tryin to give him bad advice for me, ill take cubes all day too

impaled

rotating assembly weight will definietly be minimized, i realize that the weight has a greater effect than the length of the stroke to a point.

it is not that money is no object, as it is to a point, but thats not the main concern.


-------

TPI is right, and the approximate power band i am considering is ~4500 to 8500.

as far as use goes it will be mainly used for drag racing, BUT i want to be able to drive it to the track.

as far as fuel goes, that depends on one thing, when E85 is scheduled to hit FL. i would like to use E85 due to the higher octane rating, OR possibly run alcohol. i am not sure at that point, i am more in the planning stage than the acutal building stage.

i have multiple goals with this engine. i want it to be hi-revving, even if i do sacrifice a very little bit of power. i want the engine to at least survive a year of racing, then i will probably do a partial rebuild on high wear components (bearings, new rings, oil pump, possibly cleaning up the cylinders if necessary, and certain valve train components).

tpi user

the reason i really didnt debate this point any further was because i wasnt sure how much the car would actually be street driven,not much by your answer i guess. i mean if your gonna go pick the kids up from school then go to the grocery store to get mama a few things ,then head right over to the track you might have some issues. but if you drive from home to the track, do 4or 5 runs then drive it 15mins back home u might be fine,with race gas the whole time, go for it.in a 95 percent race engine 5 percent street engine ,rpm always wins.because rpm is horsepower.larger bore shorter stroke is gonna make more horsepower always,provided you have proper gears stall an intake.a 434 may leave a length or so on a 377 but by 330 ft its all over,imo of course.if hes leavin at 7000-7500 an shiften at 8500 -9000 hes always makin peak horsepower,not peak torque a 434 is always at peak torque fallen back to peak torque i guess im sayin.im not sure if i worded everything correctly but the idea is there. us mainly street guys sometimes track guys will always prefer tq because its what feels good on the street. go ahead guys tell me where im wrong, its just my opinion an i doubt impaled is gonna base his decision on what i or any1 in this forum says lol thats why its called debating

impaled

yea, you hit it on the head. my goal is all top end HP, i dont really care about torque.

i am going to be building a G-Body that will be the more streetable drag car.


dont take this wrong guys, i love thirdgen, but does anybody know of any SBC engine building forums?

tpi user

im not sure off the top of my head. but if you maybe google it you might find some info to lead you to a forum like that.

impaled

i have been looking for one for a while, and still no luck.

it really isnt necessary, you guys take good enough care of me... lol.

jwscab

if you have the 400 block already, buy a forged 400 crank, put lightweight high compression (12 -13 to 1)forged pistons in it, and forged i beam rods(lighter).

then get a killer set of heads to bolt on, and sturdy valvetrain. beehive springs, titanium intake valves, and stiff roller cam valvesprings. something that will flow upwards of 280cfm

run a solid roller with at least 245-250 degrees duration at .050"

single plane intake, and an 850 carb. or are you interested in efi? if so, efi single plane with 4 barrel throttle body, and probably alpha-n ecm control.

wicked high rpm motor, that is barely streetable. run a manual trans behind it and you can still drive it on the street.

Sonix

iTrader: (1)

There is one or two engine building forums, but you really have to know your stuff before posting, or else you'll get laughed off.
Ahh I love a good lively debate, no doubt about it!


Nah! HP = cubesxRPM (basically). I forget the actual "formula", but if you have more cubes, and spin it to the same RPM, it'll make more HP. RPM is hard on the motor, if you can use more cubes, and get away with spinning it 500-700RPM lower, and get the same HP, i'd go that route. Easier on parts.

Best way to be sure, is to grab desktop dyno or something. Throw in some parts. Lets say you're serious about a REAL high HP NA motor. I'm talking 15-18* heads, like a 700HP NA type of setup.
Throw that together, with an 11:1 377 cube 400 based engine. Redline of 7000RPM on a 260* solid roller cam. See the HP and TQ curve. Now ONLY change the cubes, go up to a 400, then a 434, see what changes. I'll bet you get more HP, and TQ, and the curve shifts a bit lower. You can bring the cam size up to shift the curve higher if you want, but the gist is that you get more HP with more cubes.

What you're thinking about now, is comparing a high revving race engine with small cubes, to a larger engine with a very low RPM limit. Rev the bigger engine higher and make even more HP!!!

mike_23us

High revving......Why not a 302 it'd be different

tpi user

ya me 2 sonix i love a good debate 2lol but any way dont you think the piston speed in a longer stroke motor is gonna be way 2 much for any kind of reliability ,not to mention the rod angles are pretty crazy as well. impaled didnt specify heads so im gonna assume hes gonna use 23 deg heads afr 227 would be perfect imo as they flow about 330 at .65o hes not gonna have enuff airflow on a 434 to support 8000 rpm. i havet broken out my tuners mathbook yet but im ready sonix lol. im sure you have seen these books they tell you how much airflow u need for a specific cid for max hp and they tell you how much piston speed in fps with rpm an stroke blah blah . rpm is horsepower. their will always be cotrovery one way or the other as to whats better. but i see your point about knockin some rpm off like 500 or 700 or so. he must be real hung up on the 377 ci thing an thats fine. but maybe we have gone off topic he said 400 ci an if that wasnt gonna work he asked if he should just build a 383 or a 350,ah crap scratch that. he said if his 400 block wouldnt work would he be better buildin a 350 or 383. just get a dart block or a bowtie block an build the 377 cause that will smoke a 383 in a racin enviroment. lets argue on this one its easier lol.

impaled

as far as components, forged or billet crank, definitely I-beams, i am still not sure on compression since i am unsure of the fuel. as far as heads i am thinking either the AFR 227's or 230's. at this point i am thinking that i am not going to go with an aftermarket block.

i was thinking solid flat tappet but that i would be willing to sway on, i havent done that much thinking about that yet... opinion is definitely welcome on that aspect.

i am not totally sold on the 377 thing, if i start digging a little bit harder i may go with a 406, BUT i will not stroke the 400 at all.

Sonix: i would appreciate it if you would PM me one of the sites for the sake of further research.

Sonix

iTrader: (1)

definately I beams? Why's that? Typically H beams are stronger?

I think you should definitely hash out the entire plan, before buying ANY parts.
A solid flat tappet? Nah, solid roller. Why cheap out on the *brain* of the engine, when you have expensive parts everywhere else? That's just silly.

I don't know of these specific websites, but like I said, I think you have a lot of research/learning to do before going on there anyway. Read on the drag racing forum here. I know xpndbl3 is a member. I would guess IHI and maybe even Stephen_87Iroc know of similar engine building forums as well.

Orr89RocZ

iTrader: (20)

for research i'd look at speedtalk. BUT dont post unless you really have an idea of what your doing. Top engine builders in the country use that site

MN246

I wouldn't use flat tappets in any performance engine, but especially not in one I wanted to use at high rpm. Flat tappets are much less reliable than rollers, not to mention that they can't handle the duration at max lift that rollers can.

Orr89RocZ

iTrader: (20)

for 7000+ rpms, go solid roller. you have to for best performance and stability. NO shortcuts here on this build

tpi user

i orr gotta go solid roller, but can you believe that cup engine builders still use 5o year old plus technology on their engines ,they still use regular old flat tappet cams solid lifters. but the only reason they do this is cause nascar rules make them or they would definately use roller wouldnt u agree? i mean geez 9600 rpm on a flat tappet, must use lots of titanium in those engines lol.

88IROC350TPI

To be blunt, your entire build is unrealistic. It would be very expensive, very impractical, and not perform anywhere near what something built properly with the same amount of cash invested would. All of this just so you can rev your motor high? It'd be smarter to modify your tach to read higher than it would be to lose HP in favor of high RPM's

You'd be better off buying one of those E85 Shafiroff 434's. It'd run on the fuel you want, make the HP you want, and you'd be shifting it, probably, at a little over 7000RPM.

Orr89RocZ

iTrader: (20)

Are they limited to stock lifter bore size (chevy guys that is?) cuz its good idea to bore the lifter bore to accept Ford sized lifters as they are larger

I didnt think they ran that high rpm and those flat lifters in those motors

Apeiron

Only if you can't run rollers.

ross

I think to reach the power levels you want you are going to need a large displacment motor. And you are still going to see the 7500 rpm shift points. I shift my 434ci 7500 and with a nitrous converter and gear I shifted 7800 rpm. It makes about 650hp at the crank and runs 10.05 best on pump gas NA. I built this motor my self as with all the other combos I have used in the past. I also had a 380ci motor this was a 4.155 bore with a 3.50 stroke and a 6.00 rod pump gas motor it ran 11.00s to 11.10s on motor and sprayed with a 275 tune 9.70 At 140mph. I can point you to a good builder in the WPB area if you want.

1989GTATransAm

iTrader: (3)

Couple of suggestions. There is a new block out by Dart that has all the good features you want and sells for around $1500. It is available in either a 4" bore or a 4.125" bore for openers. For your use obviously go with the 4.125" bore

The 4" bore version has Dart part number 31161111. I will have to find the other part number for the larger bore. Anyways you can bore it quite abit and it comes with splayed four bolt mains. Also it is ready to accept the L98 roller cam components. Comes completely machined except for the final bore.

I would also use the longest rod that will not get into the oil ring with the piston pin. This will cut down on weight. I would also use the lightest crankshaft I could afford.

For heads I would check out the new AFR Eliminator series. Now for 600rwhp that would mean you would need around 700hp at the crankshaft. That works out to over 1.85 horsepower per cubic inch. That will also call for a power adder or big money.

Edit: looks like the part number for the 4.125" version is 31161211.

impaled

that block is definitely appealing and i will definietly consider it. for some reason i cant find really detailed specs on it and the PN doesnt match on dart's website.

as far as heads i was looking at the AFR eliminators.

i am not necessarily dead set on anything... i am looking for opinion and experiances so dont think i am closed minded at all , even as far as the stroke goes. the high revving is something that i am interested in, but realistically as far as the power goes, i would like to hit 7500, but if i would be better off at around 7000, i would be fine with that. i think for some reason i am coming accross as dead set on what i want, but as previously stated i am looking for further experiances and opinions (which you have all been great about,and thanks and i really appreciate it).

88IROCTPI, i see where you are coming from and understand that, but in reality most goals in the beginning stages are unreallistic, some more so than others.

Apeiron

The stroke isn't going to have anything to do with that. You could build a 377, 400 or 434 that could spin that fast, or even faster.

MN246

Are you serious?? 50 year old technology in a NASCAR engine. You'd be hard pressed to find many things in a current Cup car that are done the way they were 50 years ago. Cup and Nationwide cars use flat tappets, however the truck series uses full roller valvetrains.

One of the tricks the Cup teams use is springs on top of the lifters that help keep them seated on the cam. You'll also notice, if you're ever in the garage following final practice, that all the Cup teams change valve springs before the actual race. It's a lot to ask of the valve springs to turn 9K+ rpms for over 3 hours. They only need the motors to last for 500 miles, so you can do some exotic things that wouldn't apply to an engine that was going to be run on the street.

Orr89RocZ

iTrader: (20)

bascially AFR's hydra-rev kit.

tpi user

hey mn246 ya a solid flat tappet is 50 yr old technology i didnt say the rest of the engine. of course its askin alot of a spring to last 9500 rpm for 3hrs they are the part that most likely fail in the engine even though they change them after final practice if it wasnt they wouldnt change them

MN246

TPI, I agree that the basic architecture is the same, but even the lifters have changed. If you consider nothing more than the metalurgy used to produce the lifters, there is a vast chasm of difference in technology levels.