superstock top end combo

[Bubstr]

All the bigger heads are going to do is RAISE the peak HP rpm and/or pk torque rpm. There is no crutching that with a cam. Some think so but all your doing is cutting back the duration and killing where the heads were made to run even more.There is no substitute for having the proper heads for the cubes/rpm range of the engine.If your going out there and dropping down to 3500 rpms in the corners and you have monster heads you're just defeating the purpose. You need a combination. Everything works together.

This is the truth, the whole truth and nothing but the truth. COMBINATION.

You first weigh any restrictions, such as carb size or RPM limitations. You then find or make a port, valve and head angle that will make a useable horsepower curve. You then pick a cam and carb to fit the needs of these. When you start tweaking with cams, timing or carbs that where not meant for the combination, you will always lose something for anything you gain. This usually makes your power curve shorter in duration or lower on power. This is why a good head porter gets the big bucks.

With this said, you sometimes can add to the top end of your power curve at the cost of the bottom. There is no free horsepower. The real trick is getting a good curve and gearing for it.

[let-r-eat]

You are on the right track Prop21. The 220 heads are fine and that 7cc dome srp piston. You don't want a 950cfm carburetor. I would get the seat duration around 292-294 and those heads can use around 300-302 seat duration on the exhaust. A good 1 3/4 header and your set.Terry is giving you some good advice on the cam. I would run a little shorter on duration than he would with those 220's on a 383 but I don't know how momentum your track is. You can probably run 254 or 256 intake and 260 262 exhaust on 106 Intake centerline on a 107 or 108 lobe center.Isky is my cam of choice here because that's what I have experience with but Comp/Crane/Erson/and Mark at Bullet can point you in the right direction. I like Crower also...............don't get me wrong, their cams are just fine. The few degrees on the cam isn't going to be that big of a factor. You just need to run the engine in the RPM band it's going to be designed for. Those 220 heads should work pretty (not a nice word)(not a nice word)(not a nice word)(not a nice word) good on a 383 turning 7800.

[propit21]

Thanks guys, yes I wish we could have a little better combo for the motor but this is what we have and trying to make the best out of it. With that we are on a 7800 rpm chip rule so I know we are limited a little with the heads we have. If I understand right the shorter duration will bring the peak power down in the rpm. The isky cam is installed straight up so it will be at 106 intake centerline. And the lobe is also 106. How much would a wider lsa help bring the rpm range down.

[propit21]

A little update, got the motors together by the engine guy. BTW looking for a good engine shop person in southern california, we are sick and tired of the guy we are using. Went with a isky cam for the 383 the cam 201571. Would recommend isky racing cams to anyone looking for a new cam or valve train part. What a stand up company the customer service is the best you are ever going to get, Ron Iskenderian himself helped us on the phone for like 2 hours called our engine guy himself to explain so issue we were having with the valve springs and gave us a great deal on a new set of spring since we got the wrong ones. Awesome company can't say it enough if you need any valve train part go with ISKY.

Anyway haven't ran the motors yet just picked them up but our hardheaded engine guy said the cam we choose which is the 201571 isn't enough cam for our motor and its to small.
cam specs
duration at .050 int 258/ext 262
valve lift int .570/ext 5.80 thats with 1.5 rockers
lobe center 106*
ADV duration int 286*/ext 290*

@ .050
intake open 23 btdc exhaust open 57 bbdc
intake close 55 abdc exhaust close 25 atdc

Our engine guy tells me i don't know what am talking about and that the motor is going to lay down on power for us. I am going on what i ve been told here and the little ive been learning about cams. I have called isky and asked them about the cam and they agree it should work just great and should be happy with it. Just looking for a little reinsurance that we made the right choice in cams. Again its a 383 with light weight internals, 6 inch rods 7 cc domes, world motown 220 heads, hurrican intake with the isky valve train.

Our engine builder then went ahead and assamble our 355 back up motor witha cam that he had that he said will be better then what we have in the 383 yet he won't tell us what he put in the motor. the only thing he told us was valve lash setting and it had more lift then the isky cam. the 355 motor has double hump 2.02 64cc chamber heads ported and polish heads with victor jr intake, 6 inch rods with 7 cc domes. What is everyone opinion on this should we just run it and see how it runs or try and find our what cam he put in it. Long story short we are looking for a new engine guys.

Thanks for listining

[RaceTechKs]

Propit21: The thing I must ask is...WHY did you not do what these guys told you too and trash the Hurrican Intake. ???These guys give good advice for free and if folks dont listen they wont keep giving it to you when you ask them again. And your engine guy may be right, the 355 may run better as long as you keep using the wrong intake on the 383. NOW: If my engine guy would not tell me what he put in my engine, all I can say is SEE-YA......Hes a joke don't go back.

[propit21]

I know I agree with all of you I do. I believe we will change it soon but it was just one more expense right now of a high $$ bill. We figure when can change the intake out a little later on. Should we go with victor jr, or super victor.

[DANNY]

Super victor 2925 all the way. I know some engine builders keep cams a secret just like car owners will allow tear downs until is involves the cam as long as it is of legal nature. Cams are a huge part in what makes an engine do what it does and many once they find "the one" are not willing to let that info out. However if my builder tried keeping it a secret we would have a huge talk or I would go someplace else as well...