hear is the deal I am building a 350 4 bolt main block with vortec heads about 9.5-1 a low end cam probably some thing like 208/212 deg @ 50 with about .448 and .452 lift I just need to know what I should use for pistons this motor will see about 150,000 miles before its next rebuild if all goes well if I go cast how much HP can they take how about the hypereutectics, I am worried about the noise of the forged but I can deal with it if its a must thanks for your help guys

Hypereutectics are fine for your application. In short words, with 9:1 compression and that small cam, this is a very mild set up and could actually usee cast pistons! Your cam isn't really much hotter than some of the factory stuff, and the compression is lower.

As you already know, forged pistons are gonna require 3x as much clearance cold to account for expansion. They are louder at startup and harder on the cylinder bores. Unless the engine is making more than 500HP, or Blown, or N2O injected, I wouldn't run the forged jobs.

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Paul D.

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68RS, 331, 10.5:1, 4spd, 3.90 9", lowered, 245-45-16's all 'round

forged or hyper. I think Keith block hypers will work. i've heard of "piston slap" but most engine i've heard with forged pistons didnt make much noise at all.

any ideas on a cam that would be under .460" lift I don’t have a shop that is willing to cut the seats for bigger springs in the heads I would like to be in the 300-350 hp range o ya pdquick did you get the # for that yard down your way

[This message has been edited by c4boom (edited 11-28-2001).]

Cast pistons will be perfectly fine for an engine like this. They are cheap and quiet. I use cast TRW flat tops in my vortec headed 350...they end up about .040 in the hole which puts my compression right at 9.4-1 with .038 thick head gaskets. Not perfect but it works...I can still run 87 octane fuel with no problems.
As far as the springs are concerned, the stock springs are only good to about .460-.470 lift...however, you can use something like the comp cams 981-16 springs and matching retainers (which are 740-16 if I remember correctly) which are much better suited for a performance cam (stronger springs) and will let you run a .480 lift cam...maybe more. I use the XE268 cam (k-kit) and have over 2 years service on it now with no problems.
My question is, do you really want such a small cam (high gears or heavy vehicle?) or are you just trying to keep the lift below .460? Whatever you decide, just remember that the vortec heads like a few degrees more exhaust duration because the exhaust flow is a little on the weak side. If you provide a little info about your gears, convertor, vehicle weight, expected idle quality, performance requirements, etc, we might be able to offer a few cam suggestions.

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'78 chevy truck-355, 9.4-1, vortec heads, XE268, vortec rpm intake, 750 edelbrock, flowtech headers and terminators.

'77 Nova-slowly progressing project.

'78 Nova-parts car?

'95 Lumina 3.4L DOHC 210hp daily driver

In all honesty, sounds like just a slightly modified engine, that isn't going to be buzzed past 5500 rpm. If you are not going to buzz it and if just naturally asperated and no nitro I wouldn't waste $ on pistons I would stay with cast. Just get some Federal Mogal babies with good rings and save the cash. I would rather see you spend the extra $ on the best bearings (Clevite 77) for your mains and rods. Just my opinion, as I don't see this engine working extra duty.

As far as cams go (not knowing but assuming you will run a stock converter and gears in the 2.73 to 3.42 range)I think you would be happy with Comp Cams 265DEH. .442I & .465E if you are using stock rockers you should be able to get away with the exaust lift as usually the ratio is slightly less than 1.5. Some manufactures have thiner lock/retainers that will just squeeeeeze the clearance you need. Call Comp Cams Tech line and get their impression on their 255DEH, it will give you the clearence you need but might not have enough balls. Too bad you can't use .470 lift as the Magnum 270H would be the ticket. Comp Cams considers it high performance and says it's their biggest cam for stock convertor and low gears (mild rough idle - ar! ar!! ar!!!) long winded but it's cold and lonely up here in Canada Eh !!

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'68 Camaro, 350 (30 over), Forged TRW 9.8, Scat 4340 Crank, RPM Air Gap, RPM Alum. heads,
Holley 770, Turbo 400, 2.73 going to 4.11, Stock stall going to 2800, Comp Cams 280H-10.
Will be adding 250 HP Giggle Gas.
(Hope to run high 11's without and get into 10's with the HUMOR BUTTON Squeeeeezzed)

Get yourself a set of "Badgers" or even cheap cast "claimer" four notch flat tops. (Prob. about $7.00 or so a piston!). Look in the roundy-round (circle track) mag's for them!

That little cam you are talking about is about one and a half steps up from the stock -929, 295hp/350 L-48 engine cam so it will most certainly make you 300hp! (Prob. close ta 330hp?). And it being real mild will give you good mileage (if you can keep your foot out of it) and will give almost stock engine life!

Go for it! pdq67

travis
it is going in a 1962 truck with 3.55 gears a 4 speed trans with a 2.58 first gear the truck is about 4600 lbs with out the bed i am going with a set of headers with 1 5/8" primaries

i am happy with any thing over 12 mpg

as for rpm's it hits about 6000 once and a while burning the local rice yes i know i am over revving it but it sounds so cool


[This message has been edited by c4boom (edited 11-28-2001).]

[This message has been edited by c4boom (edited 11-28-2001).]

I'm planning on going with a forged crank and hyper pistons, at a little under 9.6 comp ratio, how much boost could I run? I was thinking about getting one of those little blowers from weiand next year and maybe using around 6-8 lbs of boost. Would this be a wise idea?

hypereutectic pistons are brittle if you mess up with the mix with that blower the pistons might shatter that is what I learned from the research I have been doing on this sit and team chevelle site

C4BOOM, the local yard here is:

Camaros Plus Inc
97 Sheffield Rd
Manchester, NH 03103-2314
Phone: (603)627-6471

I thought it was in Londonderry but it's two blocks into Manchester!!

I know it's a truck and all but, you know, if you wanna use a bigger cam without hogging out the spring seats, there are a lot of guys making "cheater springs" that fit the stock seats and make about 110lbs closed and 300lbs open at .480!! http://www.camaros.net/forum/smile.gif

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Paul D.

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68RS, 331, 10.5:1, 4spd, 3.90 9", lowered, 245-45-16's all 'round

cool thanks fore the address any one know of these cheater springs or who makes them i didnt see any in my jegs

[This message has been edited by c4boom (edited 11-29-2001).]

c4boom,

I'll find you a name for those springs!

Crane used to make them. I bought a Crane .485"/300deg. cam and kit waaaaaay back about 1981 (sorta dates me don't it! http://www.camaros.net/forum/smile.gif)It came with these springs and aluminum retainers! I remember trying to get some replacements around 1985 and Crane didn't make them anymore.

I have friends that have bought these parts recently to run them in roundy-round bomber classes that have rules about cams and springs! I'll look in a couple of old circle track mags and ask some guys. I'll find out where to get 'em.

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Paul D.

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68RS, 331, 10.5:1, 4spd, 3.90 9", lowered, 245-45-16's all 'round

I think I am going to pick up a copy of circle track at the newsstand just for the ads http://www.camaros.net/forum/smile.gif and hay your only as old as you think you are http://www.camaros.net/forum/smile.gif

[This message has been edited by c4boom (edited 11-29-2001).]

Sorry, I though you wanted a cheap, powerful long lasting commutor engine for a tall geared car! My appology. pdq67

sorry about what? it is going to be my summer commuter http://www.camaros.net/forum/smile.gif

[This message has been edited by c4boom (edited 11-29-2001).]

i use 345np sealed power cast 3 different engines 245 lbs of cranking pressure on one. drove it for 75000 miles with no trouble.11.27 compression with a flattop and 54cc heads steel shim gasket. these are cheep and strong . i had badgers crack around the pin boss repeatedly. 345np in my car have seen 8000 rpm weee without failure. .0045 wall clearance 800 grit wall finish molly rings

800 grit wall finish? My machinist only used 280 for my plasma moly rings in my 383, was he slacking? should i have gotten a smoother wall finish? I feel ripped off now

anything courser than400 grit will chip the molly on the rings. you may have been burned

anything corser than 400 will chip the molly off the rings . you may have some ring trouble later.

C4boom, I think you would be happy with either a XE262 or 268...I run the xe268 in my 4500 pound truck with a TH350 and a 2000 stall convertor with 3.08 gears and it runs very well considering the weight and high gears, and it gets 15-16 mpg on the highway (2800-3000 rpms). Get the k-kit...it comes with the cam, lifters, 981-16 springs, matching locks and retainers, double roller timing chain, lube, and seals. You wont use the seals because the valves in the vortec heads dont have the groove for the little o-ring type seals. I would also recommend the performer (not rpm) vortec pattern intake since you are using a 4 speed.

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'78 chevy truck-355, 9.4-1, vortec heads, XE268, vortec rpm intake, 750 edelbrock, flowtech headers and terminators.

'77 Nova-slowly progressing project.

'78 Nova-parts car?

'95 Lumina 3.4L DOHC 210hp daily driver

up date http://www.camaros.net/forum/smile.gif I just sent out a check for a set of springs that are good for .600 lift without having to machine the heads http://www.camaros.net/forum/smile.gif I am so happy I can go bigger now I am thinking the comp cams dual energy 275deh it has 219/229 @.050 and .462/.482 I think this will help out the vortecs poor exhaust flow or is it to big

Cool! I'm glad you found 'em yourself. I figured you would when you said you were gonna buy a CT mag. I opened one and found at least three adds for 'em in five minutes!

Watch them carefully, they are strong but they can also be brittle and tend to wear out faster than the big ones!

Actually the set I am getting I am buying from Smith Precision Products,Inc. they contacted me after I sent out the post the set I am getting are Competition Products pn 2300 I hope with the small amount of lift relative to the amount they can handle they should be ok I think but I guess I will find out after a few runs down the strip I am hoping for low 15's