Is it possible to get heads that are too big? If so, what's the down side? What factors should I consider when choosing heads? What size cam would be needed to take advantage of 215-220 runners on a 383 and still retain a fun street car and good low end grunt?

TIA.

 

Everything has to be matched from induction to exhaust. There are many books out there that will give you some real life buildups that work well. If you aren't sure post what parts you think you would like to put together and I am sure we can tell you if they will work or not.

Just as a starter for a 215-220cc intake runner and provided it has good combustion chambers and good flow numbers ( 275+cfm @ .600 lift ) then you are looking at a screamer in a 383ci. I would go with a solid roller in the .600" lift range and 240-250 @ .050 deg duration. It will make peak HP in the 6500RPM range.

 

From my talks with dart and asking questions here on the forum. With my mild cam (flat tappet 224/234 496/520 w/1.6) I will be going with 200ccs. What really matters are flow numbers, it appears intake runners aren't good for much except knowing that a 215cc head will probably need to wound up tight to really be taken advantage of.

 

Here's what I would like to accomplish with the 383.

Weekend street driver with some grunt. Not looking for an all out tq monster to burn off the tires from a moving 60mph, but I would like to have more than the 330 rwtq I am putting down stock.

Auto transmission
3.07 geared D44
Shift around 6000-6500 MAX

383 CI
Super Victor EFI conversion
Cam 230 range @.050
Forged internals
6" Rods
Aluminum Heads
10:1 - 10.5:1 compression (92 octane gas)

What kind of suggestions would you have?

 

I'm probably gonna get flamed for this, but if you want a DRIVER that makes good all around grunt and is liveable, your duration @.050 works well on a street stroker. I'd use a good flowing head no bigger than a 195.

 

the FI will help

 

Oh and the heads I thought about using were the Victor Jr CNC heads.

.100" .200" .300" .400" .500" .600" .700"
67/64 119/112 177/153 226/188 265/207 281/217 285/220

 

Good flow numbers, but for what size intake runner?
I am assuming/hoping for you around 200 or less.
If so, I would say those are some great numbers.
(Also, what price are you looking at with those?)

 

What is the downside, to too big intake port volumes?
I just don't buy this, 'everything needs to match' bs.

also, these companies DON'T tell us something useful,
'the minimum diameter, of the intake tract'.
That number, would be useful in making the correct choice of cyl head, and other stuff.

 

The whole matching thing is true. I think I've put together every MISmatched combo there is. I agree with the manufacturers not giving more pertinent information, but the average Joe calling a speed shop doesn't know what he wants, and the tech guy's knowledge is generally limited.
Its all about port velocity and airspeed. Due to technology advances, you can get away with running a smaller cylinder head and less cam and still run hard.

 

IR is 215 on the Victor Jr heads. Only heads Ive seen so far with as much flow using 195 IR has been AFR.

 

With port injection you can use much larger/higher flowing heads than with a carburetor because the EFI will take care mixture distribution and fuel atomization for rapid vaporization.

EFI with high flowing heads and a reasonable cam will make for excellent torque bandwidth, which is what street engines are about - not peak power.

Duke

 

Yes, You can have to big of heads! I tried running some race ported Dart 230 cc. So they were more like 245+ cc on a 355 ci. They probably would have run great over 8000 rpm with 15:1 compression.

The head port volume is only part of the equation. It's the total runner port volume of stopped dead air that has to get moving when the intake valve first starts to open. So a large plenum runner single plane good for 8500 rpm will make a 215cc head port react sluggishly.

I use a smaller plenum single plane on my 383 because of my 7500 rpm rev limiter.

For roller cams I'm a firm believer in the 232 - 238 max I. duration in sub 7000 rpm 383 ci motors. Keep the static compression in the 8.2 - 8.3 range. I would not buy heads with less than high 280 cfm of flow and 300+ is preferrable.

 

YOu could put the Vic Jrs ( great heads BTW) on a 383ci but like I said you have to match components and a good expample of not matching would be to put in a cam that only has lift of ~.500" or so with those those heads. The .300 to .500" lift flow numbers what you are looking at in this case and the VIc Jr really shines at .500" lift and above so unless you are going to run at least a .600" roller cam I would say there are better heads out there for your combination.

If you do go with a roller cam and 11:1 CR etc. then you will be looking at numbers like this with the Vic Jrs keep in mind peak power will be made 1500RPM above where this dyno stopped.

Lots of low end grunt there

 

So maybe the better question for me to ask is what Cam should I be using?

383 CID
Intake: Super Victor EFI or Modified Victor Jr EFI conversion
Head: Victor JR CNC
Compression: 10-10.5

Tranny: 700r4
Gears: 3.07
Stall: 2500

 

I'm going to stick my nose in here because I am helping Vettenoob build his engine. Here is my 2 cents...My runners in my head are 227cc and flow right at 289cfm@.600. My engine has a short stroke(3.48in.) and a torque robbing tunnel ram. And only 10.4 to 1 compression. And a solid roller cam 236/236@.50 and .588lift 110LSA. Now look at my dyno chart. At 2000rpm I have 300ft of torque and by 4000rpm 405ft of torque. Now with VetteNoob's engine, he is going to have similar heads, similar compression, a better intake for torque,cam I am hinting at is a hydroller 236/244@.50 with .590lift with a 114lsa and a longer stroke(3.75in.), . More stroke = more leverage = more torque. What ever torque I have add 100+ to it and thats where you he will probably end up making. So don't worry to much about the runner volumes with fuel injected motors. Look more at the cfm flows of the head. You cant go wrong with either Track1 or Victor Jr heads...

Not on my motor, its not sluggish at all. Bet you motor is carbed.

 

First mine drives like a "ordinary" Vette. I can cruise around at 1800RPM in 4th gear with a 3.08 rear end and you would thnk you are driving a mild mannered car with alot of torque, then downshift and hammer the gas and it will smoke to tires off. You can have alot of fun scaring off ricers who are pacing you this way

The ability to have "street" manner and still have alot of power is due to the roller cam profile. Because of the roller lifters, the lift can be higher for any given duration over any other cam. This gives you the best of both worlds, a nice flat broad torque curve and HP that keeps climbing.

If you don't mind keeping an eye on the valve train I would go with a solid roller, I don't have any experience with EFI but I woiuld think a CC XR274R would be a good choice for a 383ci. You will see some serious power if go that route but remeber you have to be willing to check the valve lash especially when it is new it must be checked every 1000 miles or so until everthing is worn in, then you check 2 twice a year or so

As stated above the Vic Jrs are great heads and to take advantage of them you need to run a decent cam with them otherwise you are wasting them and you might as well buy a smaller head.

BTW when I was looking for heads I bought them after I read a CHP head flow comparison ( they tested about 40 of the most popular small block heads ) and they out flowed every SB head even the AFR 210 race ready which they are equal to on intake CFM and the VIc Jrs are much better on the exhaust side


This head has the best flow numbers of all the under 200cc heads. Offering great flow throughout the entire lift range you can see this head doesn’t just put up one big number at maximum lift. If you’re looking for great flow from a mid-sized cylinder head this is definitely one of the top contenders.



This is an impressive head. It features a kidney shaped combustion chamber keeping the combustion moving, the flow is awesome from 0.400-inches all the way up to our tested 0.700-inches, and the E/I ratio is an amazing 81%. We see a head that flows some serious air and likes high lift roller cams.


Here is an extraordinary head. It has larger intake ports but with 240cfm at 0.400-inches of lift who cares? The E/I ratio is an incredible 75% making it hard to find anything wrong with these heads. This head may be a little much for a mouse motor but it is perfect for a big mouse somewhere in the 383 inch range up.

 

We have also been talking about a solid roller for this motor. Still undecided as of yet. There's time for the final decision on the cam for later...

 

Didn't see your post when I was one finger typing

Looks like he has some help with someone that knows what he's doing by looks of the dyno graph, mine was just one pull for fun when I first fired the motor up with an ailing tranny, in the spring I will get it dyno tuned with a new TKO 600 tranny and the new 1 7/8 in. sidepipes should help get the HP up there

 

Yeah, I wanted 1 7/8" headers. But the extra $900 over the cost of the 1 3/4" headers for 10-20extra HP wasn't cost effective for me. Nobody makes decently priced 1 7/8" headers for the C4...I bought a set for painted Hooked headers, welded up the outside of the header pipes where they neck down to the flange, port matched the inside of the header, rewelded and report matched, then sent them off to get coated. Cheaper and easier than welding up my own set of 1 7/8" headers and they seem to be doing a decent job. That dyno graph was with 75 miles on the new motor. I expect more when the rings seat fully. I am also going with a larger camshaft when the motor hits 1500miles and is fully broken in.