63mako

Better flow at all lifts = better cylinder filling = noticably more power everywhere. Stock heads really need split duration cam. Way better A/F ratio with the AFR's much better match for your single pattern cam = more power everywhere. When changing heads measure how far in the hole the pistons are and try to get best quench possible. .040 is your goal.

AWilson

Pistons are/were only about a half thousanths in the hole, average of .00038. But I will measure again. so I will use a .040 gasket for great quench. Pistons are 20cc dished Weisco. With the AFR 180's at 65CC gives me a 9.4 CR. Carb goes back to Lars next week! (choke sticks)

I will go with the 1.6 rockers.
What kind of head gasket MTL. is best?

StraubTech

Your max of 5500 rpm warrants the 180s'.

63mako

I would use an MLS with aluminum heads just to be safe.
http://www.summitracing.com/parts/fel-1142/overview/

uxojerry

Popular hot rodding just did a sbf ford test using three different heads on the same engine. I don't think they did any cam swaps. The surprising result was the bigger head made more power and torque through the entire rpm band. I think it was a 363 and the head options were about the same/equivalent as 180-195-210 for an sbc.

I say this because I bought a really nice crate motor that didn't really have enough head for a hp upgrade. If you will never want to make more power, disregard my point. If you may eventually want more power, I would consider at least an afr 210, maybe a 220. That leaves a little growing room and with the proper cam, a nice running higher hp 383.

63mako

My approach is ALWAYS buy matched components for the build your doing now. 210 or 220 heads on a 383 that will rarely see 5500 and never see more is a gross mismatch. If, in the future your going bigger a set of used 180 AFR eliminator heads are super easy to sell and will bring good money.

63mako

This is a great article. Note the torque and HP does not start until 2200. See the noticeable difference in power at that level, it increases below, off idle to 2200. Look at the dyno results to 5500, The 180 hangs on to 4800 with everything else. This is a Dart head, AFR will hang on longer. Note the projected HP table for sizing and pay particular attention to this:
So how do you decide what port volume your small block Chevy should have for best results? Check out the chart Fig 4. This will give a good starting point for port volume selection for a 23 degree headed small block Chevy. A word of caution here. Do not overestimate the power you are likely to see. All that will do is lead you into a bigger port than would be optimal. This leads to less power than you had hoped for. At the end of the day a little too small is better than a little too big!
http://www.dartheads.com/tech-articles/port-volumes/

AWilson

This was great. I totally get it. And why would I sacrifice performance now for what I MIGHT want some day in the future. I dont want to cheat myself out of experiencing a low end torque motor. If I want top end someday I will build it. Then Because I did both right I will see the differences. It just goes back to figuring out what in reality you will be doing with the car. I want low end off the line fun. I'm buying 180's right after X-mas!

diehrd

Be careful .. GM uses a 210 port on a 350 performance crate motor .. To see graphs and get advice i understand .. Just think it through, I wish I had a little more on a build I have done.

GM also uses a 238/242 595/575 112 cam in a 350 ... Idles so well and pulls so hard that the experts on this and other forums would tell ya that motor cant run and make power.

I knew that and still let myself be persuaded .. I had a zz465 Got videos of it on normal cruse and power blast .. Good little mouse.

I would go 210 heads .. even 220 afr .. Use a cam profile that allows for a bigger lift to max head potential yet dont get a duration so big you have idle issues.

Remember even for fuel efficiency the easier it is to intake and expel gasses the better your going to be .. Period .. As far as velocity pay attention to the intake manifold , that will have a big impact on port velocity and get a big header .. Dont go with the idea smaller tubes make torque larger make top end that is another myth

AWilson

I appreciate the comment but then why would the all respected Vizard make this comment with graphs to prove it and why would AFR, who makes by all accounts the best or equal to the best heads recommend their 180's for my short block? It is not like they don't have other offerings. I am not planning on changing the cam.

cv67

Last real life test I saw (from someone very credible here) with a similar build lost 10lbs of tq with the 195s over the 180 but gained 4hp peak with the 195 if that helps.
Yrs ago I ran a 215-220 cc head on a sbc similar weight car almost exact same cam 3.08 gear 2800 stall it was a DOG no matter what I did. Maybe 14s in the 1/4 if I was real lucky
It lost responsiveness, low end mmph ran about the same midrange had just taaaad more up top but hard to notice really'by that time it was out of cam and intake.
I was bummed....was advertised as a 200cc head poured closer to 220. I was too young and naive to check them.
Dont get sucked into the huge everything/future mystery build syndrome youll hate how it runs. BTDT!
Youll notice a night and day difference over your camel humps.

Jason Staley

Using a 210cc head with a roller cam shaft and a flat tappet engine is going to produce different results, and even with a roller cam with a much faster ramp rate, the GM crate motors still loose torque at low rpm's.

With a flat tappet cam only reaching .480 lift, most of the time your valve lift is going to be below .400. It this range the valve, valve seat, short side radius, and shrouding in the combustion chamber is going to dictate flow and not the over all volume of the port. At .100 - .300 lifts, the area just around the valve is the restriction point, not the port size. If you figure up the flow area around the valve for .1, .2, .3, etc. of lift you'll see what I am talking about.

diehrd

Because your asking for a motor you could build with an iron head you might as well use cast iron vortec heads and save a lot of money.

Would AFR tell you that ? No one else in this topic is pointing that out but it is something you should be told.

You have a chance to do it one time , so if your going aluminum heads why go with the smallest head ? Or such a small cam and have such small power aspirations .. Your torque monster will be about 450 or less, a tq monster would be 550 and up ..

And the GM crate motors that lose torque you can point directly at the cam which is a zz4 cam . Put the hot cam in that same motor change nothing else you get 430/430 , now put the cam I posted and get 465/440 thats all on 350 CI ZZ4 block , Fast burn heads and a cam change .. It is 383 power ratings out of a 350 and is very street friendly ..

63mako

The OP wants an engine that performs off idle to 5000 with a peak RPM of 5500. Why would he build an engine that has peak power over 6000 and will pull to 6500+ knowing to do that he would give up noticeable power in the RPM range he uses most. Peak HP is just a number. Torque wins races. Torque in the range you use the most is the most enjoyable and powerful to drive. OP would give up a lot of power going to vortec heads from AFR 180. The AFR 180 flows better with a better I/E ratio than almost every head 200 CC or less made by any manufacturer. The 383 with AFR 180 heads will perform noticeably better than a Brodix IK200 or Dart SHP 200 or a GM Fastburn 210 especially in the power range he wants. It will have better low and midrange and equal power and throttle response up to about 5000 RPM than the AFR 195. You need to listen to what the OP wants not what you would build. A 450 HP 383 that pulls off idle to 5500 is a lot better build for him than a 525 HP 383 that pulls 2500 to 6500. What you add up top you give up on the bottom.

AWilson

About 7 year ago I started a thread about picking a cam. It is the current cam in my car. It was very difficult and i think there were about 175 posts but I picked this cam for the same reasons I have now. BUT, I was told the heads would be my limiting factor and that I should understand that by wanting to using the numbers matching heads and intake I would be giving up 75 or more HP. Im done with originality. I want the HP. But I want it to act like a regular car when I put the top down in the summer and take the wife out for ice cream. I don't want a vibrating snarling machine then. But when I am alone and want to step on it, I want enough performance so that I feel foolish. If it was so simple as to put big everything in, there wouldn't be much discussion needed on a topic that seems to go on forever. To me that means there are subtleties that people don't get or don't want to be true. I am going 180's with the current cam and AFR recommends a Performer RPM intake. We will see what happens. But here in the Chicago area the salted roads will be here within 2 weeks! And won't be washed off till April or May so I won't be able to report till then. But I will be able to give status updates.

diehrd

I never said go biggest I am saying go in the middle . But go ahead and build it with a tiny cam and small heads .. Just do not call it a torque monster because it is anything but that ..


GL ..

96 lt-4

It is all about intended usage.Some here are missing the point and like peeing in the wind.

I am piecing together a 350 on an extremely tight budget myself for a 78 Malibu.
I have a reman 90 hyd roller cam longblock(stock z-28 replacement motor).I also have a set of trickflow 195cc heads I got for less than half price than new.While it may not be ideal I will use it as it is what I have.It may be too much head for the motor and my rpm range(5500 max),however they will still perform better than the stock heads on it.Next choice will be the cam.I have ideas and have sent recommendation forms to several cam companies as well(not looking to muddy the waters in this thread).
All things being equal I think 180cc would suit this (and anyone else in the idle to 5500 club)motor better for low speed torque and mid range.
When I built the 383 in my 96 I wanted good power like everyone else.I was not willing to sacrifice drive ability for the last 10hp.I had AFR 195's on that motor and it turned out quite well.

427Hotrod

Wow...this has been another fun one!

If it was me....I'd install larger heads. They will work better everywhere....but I also wouldn't be limiting myself to 5500 RPM. Why in the world do people think 5500 RPM is some magic number to stop at? You only go there when you're goofing around.....but when you ARE goofing around it's a LOT more fun to have one still scream at the top end. Proper tuning will make all the difference in how it drives around in normal use. I've used some heavily ported 207 CC heads on a stock shortblock 350 with an LT-1 cam and 1.6 rockers...and it ran extremely well with 3.36's in the rear.

All that said...you've got a M-21 and 3.70 gears....so it's got some challenges at low speed anyway. That's not much gear for off the line acceleration...even less than a set of 3.36's and a wide ratio trans...which still isn't much.

With the cam you've chosen....and your 5500 top end limit....the 180's will do OK. You'll be happy. That cam has quite a bit of duration for the amount of lift it's giving. Usually used on engines with stock type heads. The added duration helps crutch them a little and the low lift is because the stocker heads aren't going to do much above .500" without a lot of work. A different cam could make a lot of difference in this combo...even with the 180's.

JIM

96 lt-4

In my case 5500 is the limit in this application for the reman shortblock AND the TALL gears in rear.

Cool Rocking Daddy

Yeah, they do use a 210 cc head. It's called a FAST BURN and has a small cross section area for very fast velocity. Most of that 210 cc is in the bowl of the port not the runner. DON'T BE DECEIVED! The 180 head is the best choice for what the OP wants to do. I also read about the larger heads producing more torque and horsepower across the board. Fine and dandy. But how quick does all that torque and hp come on when you push the giddyup pedal. Is there a lag, a sogginess? Very likely. The smallest cross section area port to match your rpm goals properly matched with cam, stall, and gears is the answer.

Everybody and their uncle touts the AFR heads so why the hell won't people listen to the people who design and build the AFR heads as to what size is best. By the way, OP, you can buy 180 Profilers that will flow equal to the AFR heads but cost $500 less. That's the way I'm going. Good luck.