I just had a motor built buy a scam artest in dighton/taunton ma. named chris murry .i dropped off a 200 mile never raced 383 with 700 hp to freshen up because it had been sitting for a long time,he first told me about 1500,and a few weeks a month latter he said everthing was junk and gave me a price of 4500,i could not afford it he said he could build a 450 hp 360 out of it for 3000 i gve him 2000 down ,it took him 9 months ,i told hm i wanted to run 93 octane and want a wild cam,he jacked up the price to 4800 i got back a slow motor that needs race fuel to run he broke it in and cooked my headers and after he set every thig wrong ,i reset the timing and carb when i complained to him about anything he said it must be something other than the motor but i have overkill with the best of all new parts,i asked him for the old parts bach 13.1 pistons steel bal crank missing he said i went threw his scrap piles not there hmmmm.why did he not use these parts i i am running race fuel anyways.i want to try to make this motor work before i take the loss and drop another 5000 for a 500 hp big block.it is in a 72 pro touring camaro,it is a 350 .060 over ,speed pro flat top pistons lzz56f pistons,scat cast crank and rods..020 milled off for 0 deck hight 10to1 compression,dart iron eagle heads 205 intake ,the cam is comp cams #12-212-2 480/231 w/110.0 lobe seperation,a old edelbrck single plane scorpion manifold,800 edelbrock carb,msd ing,and dist.,big tube hooker headers flowmaster ex/with electric cut outs,im running a 4 speed,12 bolt w/373 gears.and a un used nos snipper system. the car was susposed to be street driven,road raced,and drag raced,it hasa cage and fuel cell all the safty equipment. the funny part is the 100 350 from a swap meet was much faster.the problen is that its slow no torq and i should not need race fuel if not used it wont start drive and has severe run on.i tryed to adjust the timing,the carb,it sounds like a race car no hesitation scipps or pops. the plugs look good.the oil is clean what do i do?   

Sounds like this guy skinned you pretty *** good. While motors don’t care to sit a long time without at least an effort to pump some lube thru them on occasion, they don’t typically rot out either. If kept inside, even unheated, with a shot or WD40 down the intake and up the exhaust, then plug those ends to keep the atmosphere, bugs, and mice out the engine will keep in good shape for a long time. So you probably didn't need to dive into berfore lighting a fire in it. I believe that in the state of Massachusetts he is legally obligated to present you with the removed parts, I expect he absconded with them. Sounds like grounds for a law suit to me, perhaps the state would even like to present him with criminal charges. I recommend you talk to your attorney and the State’s Attorney General Office about this.

OK let’s peel the technical problems apart. First coming from a 383 to a 350 to a bored 360 is a really big deal in torque development. The 383 makes a lot more torque through out the power band than a 350 and in a heavy car like your Camaro this is what you’re feeling and timing when it launches. The only way you can get a similar reaction from a 350/360 is by building the engine to make more top end horsepower in an RPM range that a 383 can’t, by virtue of having to mange greater crank assembly mass, be rev’ed to. Then to use all of this extra horsepower; you’ve got to gear the daylights out of the rear end way up in the 4s or 5s to 1 in order to get all that horsepower converted back into useful torque, which is the stuff that moves the car. OK, that’s the theoretical world. In reality there isn’t anyplace you can build a 350 for revs that you can’t build a 383 to go there also. So we're back to a 383 develops a fatter power curve period and yours is gone.

So unless you want to build a 7000 RPM plus 360 to give you that old hard launch feeling what can you do.

Well, it's like this!

The Comp 12-212-2 cam isn’t all that hot in terms of a racing cam, it’s just a higher end street cam. Unfortunately it’s hot enough to degrade low and middle range torque pushing the total power band up the rev range, but not het enough to really deliver super high rev power. You need to either get really serious about cam timing along with more rear gears or drop the cam duration back 10 degrees or a bit more and go to a dual plane 180 degree intake. Speaking of intakes the Scorpion wasn’t all that good when new, it only works up on the top end which is a tough place to run an engine on the street. I’d look to the Torquer for a better street/strip cam that leans toward the strip. After that it’s dual planes like the Performer for better street manners at the expense of some top end on the strip. Surprisingly the Performer doesn't give up all that much at 6000 or so compared to a single plane intake. 

The big tube headers are another problem, they just don’t allow the engine to develop torque in the mid rev range, to use them the motor needs to be wound up tight all the time, again not very pleasant stoplight to stoplight. The exhaust velocity just drops off at RPMs less than the torque peak and unfortunately your cam selection has a lot of I/E overlap which needs high exhaust gas velocity to work. A smaller tube header say 1&5/8s inch, especially with AR cones, would provide more lower/mid punch with surprising little top end loss. Wrapping your headers with heat tape might also help by keeping the gasses hotter, thus expanded longer. This will pick up gas speed inside the pipes which will help the overlap to work harder.  Problem with tape is it’s expensive and it totally cooks the pipes in a fairly short time. You said the headers were cooked by his break in, this is typical of some problems that indicate one or more things about the engine's set up; typically an engine that’s running lean, using too much nitrous too much of the time, or incorrect timing which could be cam to crank and or ignition to crank.

I’m not sure which Iron Eagle head you have, the 2.05 intake comes on heads with 200, 215, or 230 cc ports which also include a choice of 64 or 72 cc chambers. Starting with compression given a .020 decked block and flat top pistons with a 64 cc chamber I compute your compression as 12.2 to 1, that’s way too much for pump gas and a cast iron head. Assuming a 72 cc chamber I peg it at 11 to 1 compression, still too high for pump gas. You either need a lot more cam with a lot more overlap combined with 4.10 to 5.38 gears. Or you need to get rid a 1.5 to 2 ratios of compression if these ratios are real, run a compression test, anything over 180 pounds is unacceptable for premium grade street fuels. Lastly, all these port volumes are for a high speed and or big displacement engine. For a 350 /360 the 200 port really likes to work from 5 to 6 thousand RPM. The 215 cc port another grand higher, and you ain’t got the cam for 7 grand. The 230 needs to be on a flat out drag engine with 8 /9 grand on tap or a 383-406 that turns to 7 or so. This indicates the engine needs to make more revs, the displacement needs to go up another 20 inches or more, or the heads need to be replaced with those of smaller ports to fit the existing displacement and rev range.

Now for the hard part, in my long experience the Carter or the Q-Jet which ever you’re running from Edlebrock is a poor wide range performance carb. They are hard to dial in and are inconsistent over a broad RPM range. They’re fine for a moderate street machine but when you need to bridge street and track or want to run competitively on the track there’s only one carb, Holley, or its clones that fits the bill. Plus 800 CFM is far more than a 360 can use, this adds to a loss of velocity within the intake which again combined with lots of cam overlap, intake and headers makes for lazy cylinder filling. A Holley 650, 670, or 700 would be a much better carb choice both in adjustability and CFM matched closer to the engine’s requirements. So read this as your Comp cam, Scorpion intake, too big of header tubes, and 800 CFM Edlebrock carb are all conspiring against this engine making enough mid range torque to carry the Camaro through to where there’s some horsepower.

Again for ignition I don’t exactly know what you’re using MSD makes a bunch of ignitions. My choice would be all electronic, I really like the new E-Curve but MSD has other choices as well. You have to manage 3 basic things with the ignition. First is the base setting, next is total advance, and between those two places is the rate of the timing curve. The total amount of timing the engine will accept is about 36 to 40 degrees. The typical distributor is designed for a static setting of 8-10 degrees with about 28-30 degrees in the advance mechanism. The trouble a lot of people get into is changing the base setting to more than 10 without subtracting those additional degrees from the advance mechanism. This leads to over advancing the engine which often shows as better mid range performance but the engine falls flat on the top end due to excessive total amount of timing lead. The curve rate usually needs to be worked on to make the engine perform at its best. With a conventional distributor this means changing springs and adjusting the vacuum advance canister for the best rate of acceleration. This is a tedious job at best if one doesn’t have a dyno. One of the neat things about a gas engine is that the burn speed is proportional to mixture density, which is to say to more air and fuel going in the faster it burns. So above about 2200 to 3000 RPM it’s unnecessary to add more advance, things just automatically burn faster in proportion to throttle opening beyond that point. But that idle to 3 grand zone is touchy and needs to be thoroughly worked to get it right. If you’re boosting with laughing gas, the timing actually needs some retard for a couple reason the first being is that this stuff plus extra fuel ups the mixture density so the burn speed goes up as previously described. The other is a materials constraint, the more fuel burnt is more BTUs thus heat generated and the stuff the engine is made out of can only take so much of that. So the retarded spark keeps these temps and pressures from getting out of hand. Yes that means you can’t get all its got.

One of the things you need to get checked is cam timing to the crank. Comp has what I think is the bad habit of machining 4 degrees of advance into the shaft, since most everybody seems to set engines up this way, they thought they’d be helpful by just dialing it in for ya. This causes two big problems, first not all installations like the cam advanced, so from a builder/racer stand point you’ve got to put the motor together, throw it on a dyno and see what it likes, this is called tuning. The other happens to the unsuspecting assembler that read a couple books the extol the virtues or advancing the cam, so in “Monkey See-Monkey Do fashion they slip in a 4 degree bushing an whoa, your Comp is now 8 degrees advanced and power is now falling on its face assuming the pistons and valves didn’t meet and kiss first.

One last thing, a .060 overbore on a 350 block, in my experience is pushing the limit of cylinder wall integrity, if the wall is “breathing” because it’s too thin for the loads imposed on it, pressure that should be used to push the piston down the bore is being lost around the rings to the crankcase.

May the Gods of power smile upon you, Bogie

I guess i will start with the cam first since every one thinks its too small for the motor,as far as the gears it has no power in the upper rpms either,i cant touch this guy because he works out of his house,i just found out he scammed another guy withe a sbc he jacked up the price on un neccery work until he told him to keep it then he sold the motor to someone else,i guess thats what he was trying with me.i guess thats what you get with a mopar guy that and mullets.  

If it's crapping out mid range to upper end, the problem may be too much compression, too much advance; too rich a mixture unless it pops out the intake which is too lean a mixture or timing off. Speaking of timing being off; the cam could but be right to where the crank is, Comp puts 4 degrees advance in the grind, assemblers who don't know this put a 4 degree bushing in there cause the hot rod books say so. If he did this you've got 8 degrees advance. Not only is the timing off but valves and pistons might be kissing with this much advance on the shaft.

A too little cam will simply flatten over around 5 grand but will pull hard to that point. Too much cam will be soft on the bottom and pull hard on the top. I rather think your engine is set up with an emphasis on top end power with the big carb, Scorpion intake and big tube headers. This will make the motor a little weak knee'd out of the hole, but it should pull mighty hard starting around 4-5 grand. That doesn't sound like the description of your problem.

At this point I think stuffing more cam in it is not the best use of your money. You need to find out why it craps out as the revs go up, please reread my original comments. I think the compression on this engine is way too high for available fuel, unless you want to run race fuel all the time. I have yet to have a satisfactory experience with octane improver and I've tried everybody's, so I wouldn’t plan on that stuff to save the bacon. Cam too advanced will also do this, as will ignition too advanced, or carb mixtures are off. I think you've got some real basic diagnostic work to do before you spend more money on parts.

Bogie

i have tried everything,it seems to be the same ,the motor sounds and revs like a race motor like a10 second car would but it probley runs 18 s,its strange it dous not miss hesitate or bog it runs verry strong,no problems except for blowing out the oil pan gaskets ,i have a pcv and crank breather? and running race fuel in a slow car.it reall only pulls a little from3200-5000 rpm and that seems to be the limmit.i want to road race and drag race this car and i hate to pull this expencive motor that woul be ok fo cruze nights and  short drives.but i am thinking of selling it and buying a freinds 550 hp big block,instead of wasting more time and money,but i cand decide if i can for shure make this motor do what the builder tol me id rather keep it.  

Blowing out the pan gaskets or crank seals sounds like too much case pressure. Seems I did a scenaro like this already was it for you?

Wow, I've seen guys build an overbore engine with standard bore pistons and the proper size oversize rings, don't laugh, it's true. The engine would start and run fine up to the middish rev range then everything would loose their grip on the walls and the power would just top over. High oil consumption and blown out gaskets and seals were another sign of lots of compression getting into the crankcase.

Another combo that doesn't work for long is moly rings on a coarsely honed cylinder wall. The rough wall tears the moly off the rings resulting in excessive blow by. These will usually show with a compression test, since the ring just can't make a tight seal. The reverse of this situation is when chrome rings are used with a fine grit hone finish on the walls. In this case the walls are too smooth for the the hard chrome to get a bite on and compression gets around the rings into the crankcase. Oil consumption is high and the engine never breaks in. Compression will test high since at cranking speed events and pressures aren't high enough to show the symptoms.

Another funny thing is an underbalanced engine. These tend to loose power off the top end, although this is not so apparent and abrupt as other problems. But the bottom end gets unstable and the pistons/rings/walls loose effective contact with all that shaken goin' on and compression gets out into the crankcase.

The way your motor is built, I'd expect it to run like a scalded ape out to about 5500-6000, where the somewhat short cam will call a halt to more breathing.  Maybe a little doggie coming out the hole given the big everything else but cam and the 3.73 gears, but it should be able to climb through that phase rather quickly.

I don't remember what you're running for a transmission, that could have an effect if an automatic on upper end speeds if it's slipping. But then there's the overpressure in the crankcase which would have nothing to do with the attached gear box. If you could get over 5000 RPM I'd expect issues with crankcase pressure and the need for a different venting system, but at these relatively low revs there shouldn't be enough case pressure to push oil out gaskets and seals. You could see see oil getting blown out the vent or into the aircleaner if one of the vent hoses makes that connection with a PCV valve set up, but still at 5 grand I can't see case pressure getting so high that it blows gaskets and seals unless someting else is going on like rings that totally lose their seal to the cylinder wall.

Bogie 

I went to a good motor shop,they told me the guy was a hack and to get all my 383 parts back so the can re do it ,they also told me the builder lied and picked all the parts himself and told them what to do.i went to get my parts back,he said he threw them all away(a goos steel 383 crank rods pistons etc.) yeh right.he sasys he built it right and came up with a its your fault excuse for everything,now i have no money  a awsome 72 pro touring/race/street car that i put over 40k into,it makes me so sick i have decided to sell it and buy a newer corvette,anyone in ma. interested?  

I think I went down this path a ways back. It's too bad that all this shop could do is confirm what became apparent. This is just theft, but it doesn't look like the chances of proving it are to good. Abont the only thing you can do is to let everybody you know about this guy.

Bogie  

you got ripped off big time. You better put a end to this guy. he taking peoples motors and making alot of money there was a outboard shop that did the exact same thing for years were I used to live  

Please don't post in threads that are long and done with, such as being two YEARS old!  

Whoops didn't look at the dates sorry