spedrace35

Do you guys think that one of these cams would be good for my 383 build? I will have to order a small base circle cam so that my rods will clear the cam.

First Cam
For Computer Controlled Engines (Will have to be special order for a small base circle cam)
Description: Hydraulic Roller for factory roller cam engines with highly modified TPI. Biggest cam for stock converter.

Part # 08-305-8
Engine: 305ci-350ci 8cyl
Grind #: CS 276H-R14
Valve Adjustment: .51in/ .51 ex
Gross Valve Lift: .51in/ .51 ex
Duration @ 0.006 Tappet Lift 276in/ 290ex
Vale Timing @ 0.05
Intake: Open 0/ Close 40
Exhaust: Open 53/ Close -3

These Specs Are For The Cam Installed @ 110 Intake CL
Duration @ 0.05: 220 in/ 230ex
Lobe Lift: .34in/ .34ex
Lobe Separation: 114*



Second Cam
For Computer Controlled Engines (Will have to be special order for a small base circle cam)
Description: Hydraulic Best cam for modified 350 TPI with improved chip, injectors, plenum, runners and exhaust. 2000 stall.

Part # 08-503-8
Engine: 305ci-350ci 8cyl
Grind #: CS XR276HR-12
Valve Adjustment: 0 in/ 0 ex
Gross Valve Lift: ..503in/ .51 ex
Duration @ 0.006 Tappet Lift: 276in/ 281ex
Vale Timing @ 0.05
Intake Open 30/ Close 66
Exhaust: Open 76/ Close 24

These Specs Are For The Cam Installed @ 110 Intake CL
Duration @ 0.05: 224 in/ 230ex
Lobe Lift: .335in/ .34ex
Lobe Separation: 112*

Ok here is the list of what I have got for my motor so far.

383 Fully Balanced rotating assembly from Eagle specialty products
stroke 3.75 x bore 4.060
6” rods (non cap screw)

Cam – yet to be determined as well as the push rods

Heads – Pro Topline, Pro lightning heads with 74 cc chambers
200 cc intake runners that have been polished
2.02 Manley intake valves
1.60 Manley exhaust valves
Comp cams springs retainers all the good stuff
Set pressure 130# open @ .50 lift 350#
Complete 1:6 Roller rockers
Heads were put together at a performance shot in my home town


Intake for the time being Ill be using the stock tpi system but Ill upgrade shortly to the TPIS Mini Ram

Headers- SLP 1 ¾” coated w/AIR

Ignition – Stock but will up grade shortly

Torque Converter – I have hard many things about going to a high stall, I heard it will kill my gas mileage, even though I wont be getting the best to begin with. If I do get a new stall I want to keep it fairly low

Trans – 700-r4 with shift kit

Rear end 4:11

Computer - its stock, when I bought the car it already had a chip. I am planning on getting the chip reprogrammed or I will get a new chip if it is not reprogrammable. I would like to wait till my car is running and take it to the dyno and have it tuned there.

That is all that I can think of right now.
Remember that my intentions are for street use mostly and little strip use, probably only a couple times a year.

And I do not plan on having a screaming high RPM motor, which is the reason why I wanted to go with a stroker. I would like to have my power from low to mid RPM’s , I don’t want to go above 5,500 RPM and the most I would want to push my engine is 6000 RPM.

Well if you guys have any suggestion of other cams that would be good for my application I am all ears. I just want to buy the best cam for my motor.

84z28350

Just did some quick calcs on dd2000, i dont have flow numbers for your specific heads so im using Edelbrock performer w/2.02 & 1.6 valves.

With 08-305-8 cam im getting 371HP @ 5k and 488lb @ 2k

With 08-503-8 i got 379HP @ 5k and 492lb @ 2.5k

So the second cam gives you a little more power.

I would go with the second cam, little bit more HP/torq and it also brings your power band down a little.


Charts:



Remember these are just estimated flywheel numbers...

zippy

i'd look into the XM270HR. it's a cam designed for marine engines, but should work fine.

270º/276º Advertised duration
218º/224º Duration at .050"
.495"/.503" Valve lift with 1.5 ratio rocker
112 LSA

spedrace35

84z28350 thanks for the great feed back! I am assuming that these numbers are from a 350 (4.0 bore x 3.88 bore). Is it hard to figure out those calculations that you did?

Quick question about the marine cam, I was thinking that marine engines rotated the opposite direction then motors for cars. Is that true or am I wrong?

zippy

not all marine engines run backward. only specific models. usually they specificly list that in the cam specs if it's reverse rotation.

84z28350

The calcs i did were with a 350 block 4.030 bore 3.75 stoke = 383ci

Ahh crap i see you were using 1.6 rati and rollers, ill have to edit my first post the numbers are going to be off...
I have also been giving you numbers for a 800cfm carb on a dual plane as your modded tpi probably wont be close to a stock one, TPI's generally have a bit more torque and less HP

Ill get the calcs with that marine cam in a min.

Edit: ok with the marine cam # CS XM 270HR-12 your looking at 363HP @ 4.5k and 494lb @ 2k so its got loads of bottom end torque and an even lower powerband but lower overall HP.



Hmmm if you ran 16:1 compression and burned methanol you would make 480HP 639lb...

spedrace35

84z28350 I am wondering, how much of a difference is there between the 383 and the 350. Assuming that you are using all the things that I have stated earlier just a smaller stroke (4.06 bore x 3.48 stroke). This is something that I have been wondering for a wile. Thanks again for all your input!!

84z28350

Not a whole lot of difference, the 350 just makes its power a little bit higher up in the RPMs and less torque than a stroker.

A 350 with everything exactly the same as the dyno graph i gave you for the 8-503-8 cam would make about 378HP @ 5k 451lb @ 2.5k

spedrace35

84z28350,
Wow that’s some interesting info!! For some reason I was thinking that the stroke would make more hp. I guess I was thinking this because of CI. However I did know that they make more torque. Thanks again for your help and info, it has helped me a lot.

One more thing, sorry to keep bothering you about numbers. Lets just say that you had an after market block and had the same stroke as a 350 but had a really large bore (I don’t think this really could be done, its one of those what if questions). For example (4.18341 bore x 3.48 stroke) this also equals a 383, but it was bored not stroked.

The reason that I am asking you this question is because I have always heard that two engines with the same displacement (but one engine has been bored and has a stock stroke, and the other engine with stock bore but stroked) made about the same power but at different rangers. I could be wrong I just want to know if it is true or not. Thanks again, I will stop asking you these type of questions now!!

zippy

this has been done with a 4.00 bore 3.75 stroke against a 4.155 bore 3.48 stroke small block. the short stroke engine in the few times they've done the test made more hp, but also required more stall to run the same number and wasn't nearly as street friendly. the power difference was about 10hp and torque was just about identical with the exception of when it made peak. obviously the long stroke made it much earlier.

84z28350

The big bore short stroke will be able to spin up faster than the long stroke. So with alot of wild cams that dont make power till 6-7k this would be a good choice.

zippy

the short stroke will spin higher without problem, but the short stroke doesn't necessarily spin up faster. if that was the case, the short stroke would have more torque at lower rpm. piston speed is faster on a long stroke engine which is why it will rev quicker. the rev quicker theory of the short stroke engine is old school theory.