stroking a 350

[jgh64pkup]

i have a 1971 350 block 2 bolt mains i wanted to know how far i can stroke it

[Marv D]

Safely and economically?? ... 383 (3.75" stroke) I've built a few 396's (3.875" stroke) but honestly the slight added power isn't worth the added cost.

[jgh64pkup]

can you stroke it to a 408 on a standard gm block

[jgreene0717]

Here is a link to Chevy HI-Performance about stroker motors.
http://www.chevyhiperformance.com/te...ker_motor.html

[jgh64pkup]

thabks for the link how well do cast cranks hold up compared to 4340 forged cranks
whats a good website for stroker kits

[Marv D]

Think of the cast crank as a $1 plate you bought at Wallmart, and the 4340 crank as a high dollar serving plate make of 'Pirex' It take s LOT more bumps, bangs and abuse to break the good plate. But when you do.... you've screwed up pretty good!

Your local machine shop is always a great source for engine kits (ask local racers where they go) . Summit and Jeggs both have VERy decent deals on rotating assemblies with bearings, rings, balancer and flex plate. One of the SE's best outlets is Flatlander racing,, some killer Carrillo kits, and everything all the way down to Scat cast stuff.

Biggest problem is KNOWING what your block needs. If it's a high mile virgin block it should clean up at +.030,,, but no guarentees. Many will need +.040 to true up the bores. If it takes more than +.040 I'd look for another block. Lots of motors out there running at +.060, but it's a shakey deal at best! If you r investing this much money in a motor,,, keep ONE MORE bore job in the bank here so your not 'all done' at the next rebuild. Pistons and rebalancing is a heck of a lot cheaper than a complete new motor.

[capev86]

if you want more pulling power, a stroker 350 is a great way to go. not much more cost than rebuilding. i'd go with the classic 383 (400 crank and .03 pistons) and run an rv grind roller cam. it will get as good if not better gas mileage than a stock 350. for maximizing every last drop of fuel i'd switch in an mpi top end. i have a 406sbc and it only dropped 1mpg in an 84 suburban 2wd with overdrive. mpi and a better exhaust would fix that.

if you watch car shows and the aftermarket, there is a custom engine block builder out there that builds 472 small blocks based on the 55-96 era engines. it has a wider bottom end for a super long stroker crank. if money were no option, i'd jump on it!

[jgh64pkup]

im looking at the 408 stroker kit from rpm machines its a scat rotating assembly all 4340 forged
rpm machine
my block was locked up and it had all stock internals
the bearings were stamped 3 71 and was never marked on the rods

[jgh64pkup]

i think im going with the 408 this might take a few years (5 or more) to build cause im a little short on cash
but it should run like a beast
my plans are a bowtie intake
intake
RHS 234cc pro action heads with a 72cc chamber
these have amazing flow numbers
heads
flow chart
they are decently priced also
how much hp and tq do you think it will make
with what cam and carb

[z400rider8787]

those heads may have great flow numbers but they might be too big. The idea is not to get the biggest everything, its make everything match and work together. Is this a full on race motor? if it is then they would probably work if you had a GIANT cam. but for street use, they might be a little overboard IMO

[jgh64pkup]

what about the intake and what size heads do you think i should use

[z400rider8787]

well it all depends on what you want,is it a street motor or race only? if you want something with decent street manners but still good power i would go with a 355 or if you want a stroker a 383, any more stroke than that on a 2 bolt is asking for trouble. you can build a 383 with a 2 bolt but if your looking to make high horsepower (400 or more) i would definatly suggest either getting a 4 bolt or better yet getting splayed 4 bolt caps and having the machine shop install them. as far as heads and intake, again it depends on street or race, if you want a street motor i wouldnt go any bigger than 200cc with 2.02 1.60 valves, if your on a budget look on ebay for aluminum heads and you can get a new set of "no namer" brand heads assembled for about 700 new. for the intake go with a good dual plane like a performer RPM and a cam with somewhere around 450-500 lift. this combo will work great together and will make easily 400-450 hp on a 383 and a solid 400 on a 355. if you are only gonna race it and dont care about gas mileage or streetability, then the sky is the limit, but still remember its about MATCHING parts not the biggest of everything. for example, if you read that your cam will have a power range of 2000-6000, you want all your other stuff to match that, ie: intake, heads, etc. also if you are building a street motor you want 10:1 compression MAX, otherwise you have to run race gas, which is not cheap. hope this helps, any other questions just ask

[youhaveamonkey]

Hey guys, this is a dumb question, but what is "mpi?"

Thanks!

[ProStreet71]

I think he is talking about MULTI PORT INJECTION...MPI.....

[ProStreet71]

You need to tell these guys what exactly you intend to build this motor for to get the most accurate information. There are many differant recipes for building an engine. But it all depends on how you want to drive this vehicle and what you are going to use it for. Are you going to drive it on the street? Race only? Street/strip? There is alot more involved than just picking out the biggest cam, intake, heads, etc. If you go that route, you will have turd that will be a pain in the ass to drive.

[jgh64pkup]

im lookin for a street strip engine that has plenty of power

[z400rider8787]

IMO the best street strip combo is a 355 or 383, that depends on your budget and where you want the power, if you want higher RPMs go with the 355 because a 383 has more rotating mass and will limit the RPMs but have more torque and more cubic inches, meaning more power overall. as for top end, go with a cam with around 450-500 lift which will give you a broad power range, say 1800-6200, there is a lunati voodoo cam with this range, then get a set of good flowing heads, you can either get some original GM heads with 64cc chambers like the old "double hump" heads and have them re-done with new valves (2.02 1.60) and good valve springs good to around .550 lift, or a set of aftermarket heads, either aluminum or cast iron with the same size valves and around 200-210cc intake runners. then get an intake manifold that matches your cam profile, an edelbrock performer RPM is a great one. then a 750 carb that is tuned for a street strip motor. use pistons that have a compression ratio of 10:1 or less, i suggest around 9.5:1, this way you can still run pump gas. add a good ignition system and your looking at at least 400hp on either motor, a little more on a 383. I STRONGLY suggest getting a 4 bolt block or getting splayed caps to start with. it would be a real bummer to spend all this money making your 2 bolt make lots of power then having it spit the crank through the oil pan. if your gonna spend all this money on go fast parts then whats an extra 200 or so to get a 4 bolt. another good start is to look through a summit or jegs magazine and look at their top end packages, they have done all the matching of parts for you, so you know your motor will make good power with one of those. another thing that is really important is forged (best) or hypereutectic (ok) pistons, if you run cast because they are cheap you will regret it. you can get away with a good set of stock rods for a mild street motor. if you can get your hands on a forged crank that would be a good idea too, you can get away with a cast one but its nice to have the peace of mind when you really push your motor. hope this helps any more questions just ask.

PS: this is what im gonna run in the motor im building:
355 CID 4 bolt block
GM forged steel crank casting #1182
forged H beam rods
forged flat top pistons around 9.75:1 comp
aluminum 210cc heads with 2.02 1.60 valves and springs good to .600 lift
edelbrock performer RPM air gap manifold
holley 750 mechanical secondary carb
comp extreme energy hyd. roller cam, with .510 lift
roller rockers.
nitrous

this will give me around 450 hp on the motor and i still have the button for a little extra punch for the strip. it will still have decent street manners but when i step on it it will put you in your seat

[Manbearpig]

I wouldnt waste your time and making a 2 bolt into a 408

Get a block with a beefed up lower.

[jgh64pkup]

if i go with a 383 i will use scat i-beam 4340 capsrew rods clearanced for stroker apps and forged pistons not sure about the crank

[ProStreet71]

Depending on your budget, I would go with a good set of aluminium heads. I like the AFR heads but they are a bit pricey, but well worth it. The AFR 195 heads would be about perfect for the 383. These heads are capable of making 500+ HP and have really good street manners. Also alumnium will allow you to run up to a full point more compression than iron. I wouldnt go over 10:1 with aluminum or 9-9.5:1 with iron. Dont waste your money on old worn out GM heads. By the time you get the machine work, valves, springs, and everything else you could have upwards of 800 bucks for an old technology heads. Spend a little more money for good aftermarket heads and you wont be disappointed. As for the crank, yes it would be better to go with a forged unit, but if you just want a hot street motor then I have used the Scat 9000 series cranks with no problems to date. If your not goin to spray hyper pistons will probably fit the bill. But if you plan on using any SPRAY then i would use forged everything. The Performer RPM AIR-GAP is an excellent street/strip intake topped of with a 750 carb. I like Quick Fuel. If you buy a Quick Fuel call them directly and they will set it up for your engine before they ship it to you at no extra charge, it may not be perfect but it will be damn close. I also would suggest goin with a roller cam especially the way the oils are now days. Things can get a little hairy trying to break in a flat tappet cam. Comps Extreme Energy or Lunatis VooDoo have good street roller grinds that are easy on the valvetrain. You will want a duration @0.50 somewhere in the 230-240 range. Best bet there is to call one of the cam manufacturers and let them spec a cam for you. Well maybe this will give you a little food for thought.... Hope it helps

[z400rider8787]

everything pro street and i said pretty much sums it up. stroking to 408 is way overkill and asking for trouble. a 383 with good aluminum heads will give you more than enough power for any street application and perform well at the strip.

[jgh64pkup]

is a big block more efficient to build such as power an tq

[z400rider8787]

I dont know a whole lot about big blocks but i know they are more expensive. But I do know big blocks can make a lot more torque and horsepower if you build them right. the only problem is they are really heavy and you will get HORRIBLE gas mileage (much worse than a small block)

[jgh64pkup]

so a 383 with some decent aluminum heads and a roller cam should run alright
what kind of power numbers do you think it would make

[ProStreet71]

383 can make 450 or more without even breaking a sweat with the right parts. Mostly depending on your budget and how radical you want to go.