Please comment on my engine build and final question:

- 77 Corvette with factory Borg Four Speed & 355 gears - street driving only

- ZZ4 Short Block
- Factory Hydraulic Roller Lifters
- Comp Cams Extreme Energy XR270HR - 218/224 @ 0.050
- Comp Cams Magnum 1.5 Rocker Arms
- Comp Cams Magnum Pushrods
- Performer RPM Intake
- Holley carb
- Cast Iron Corvette 2-1/2 Inch Rams Horn Exhaust Manifold
- 2-1/2 Magnaflow dual exhaust with X

- Felpro 0.015 inch head gasket to provide 0.040 inch quench

Question - Which of these four head choices??

Profiler Performance 185cc Heads
- 70 cc combustion chamber - 9.5:1 Compression ratio
- 64 cc combustion chamber - 10.2:1 compression ratio

AFR 180 Eliminator Heads
- 65cc combustion chamber - 10.1:1 Compression ratio
- 75cc combustion chamber - 9:1 compression ratio

 

Spec it out so it hits ZZ430 .. I did that with my ZZ4 and not only is it a perfect daily driver with great manors but has a lot of snap to the little 350 . 430/430 Is what you will end up with power wise.

If I remember right it was the LT4 hot cam , GM fast burn heads. And self aligning aluminum roller rockers. I had driven my car with a complete ZZ4 when I bought it through that first summer , After I did the clone it was quite a power increase worth the money spent. And just added the fast efi .. that was an amazing upgrade also worth the money

And toss the exhaust manifolds... Grab a set of XS Power headers with 2 inch tubes.... Stainless , very well made and 289.00

 

Why? This compromises the entire build...

 

let it breathe. You will never reach the true potential with exhaust manifolds.

 

I appreciate the comments on exhaust, but I am not interested in headers and all their problems. I could care less about winning any races, or showing off. I am just trying to build the best engine I can within the boundaries of what matters to me.

Can anyone comment on the head choice question. Profiler is taking a long time to build my cylinder heads, and I am getting tired of waiting. The 70cc head, will give me 9.5:1 compression, and I feel like that is high enough to get a good dynamic compression ratio, but not pushing the envelope on pump gas. I think 10:1 has been proven to work, especially with the right cam, and with this cam I am calculating a 8.2 dynamic compression ratio, which seems inline. BUT, my biggest hesitation is that I do NOT want to push any margins, since I really don't care about racing or bragging about HP numbers. As I said, this is a street car.

 

With no disrespect , Anyone with header issues is doing something wrong or bought thin flange headers. Also Your best bet would have been to buy a complete ZZ4. It is proven , 355hp and very cost effective with a good warranty zero hassle , zero wait time.

 

I'd go with the AFR 65's, great heads (just in case you wish to clone the 430 later on as diehdr did).

 

A ZZ4 uses Vortec heads with centerbolt valve covers, which do not look original. Not interested in modern looks. I grew up looking at late sixties and early seventies muscle cars, and that is what I want to see when I open the hood. My interests are not based on performance at the sacrifice of the look I am connecting to. If I wanted a late model Corvette, I would have bought one.

I also have a difficult time ignoring the endless posting about excess heat, burnt plug wires, cooked starters, and the fact that nobody even makes a bolt on head / muffler setup from the exhaust gasket to the tailpipe. I hear stories about having to put dents in tubes to clear parts, huges postings on trying to control heat into the car, etc. And all of this for what, 15HP at 6000 RPM that I will never see.

I do appreciate torque, so tell me what increase in torque will I see at 2500-3000 RPM if I were to choose headers over large exit 2-1/2 Corvette rams horns. Give me a number I can think about.

 

Thanks for answering my question. With the 65cc AFR heads I will be at about 10.1:1 compression. From what I read, this is no issue with 91 octane, but that is what I am concerned about. Last think I want to do is have detonation issues for whatever gain this gives me. WIth the 75cc AFR head, I will be at 9:1, which starts to make me feel like I am really giving up.

Every decision I make is based on the way I intend to operate the car....but trying to make it as torquey and fun to drive as possible within my limitations. I understand that means I am leaving HP on the table by using rams horn exhaust. But again, I could care less about what happens above 5500 RPM.

I have posted questions in the past about using good flowing heads with more restrictive exhaust, and most people commented that even with restrictive exhaust, you still benefit from the better flowing heads as opposed to poor flowing heads. I was perfectly content on possibly buying Edelbrock RPM heads, but problem is when you look at the dollars, you pay MORE for less. Especially with that old school combustion chamber they use on the 70cc head.

The Profiler Heads have numbers almost as good as AFR, but cost less than Edelbrock RPMS, Brodix IK180, Dart Platinum 180s, and certainly AFR heads. Do I have more head than I need with Profiler, I think yes, but it cost less for more. Whats the downside?

The only part of my package that people disagree with is the exhaust manifold. BUT, even David Vizard talks well about the 2-1/2 inch Corvette Rams horns, and for me, its good enough. I actually considered headers for awhile, until reading this forum changed my mind, but what sealed the deal was finding an excellent set of OEM GM 2-1/2 rams horns for an excellent price. Now, I have none of the header issues to worry about.

 

There heads accept center bolt and conventional bolt on the ZZ4 if I remember correctly , and your long list of header issues are not header issues , your listing Buba errors . Magna flow sells header back dual kits . And with a 1 5/8 header your tq will benefit over those ex manifolds. I would say 25 plus pounds easily down low and more likely more

 

You may say that about headers, but there are numerous postings on this forum on excessive heat into the car, loosening attach hardware, having to put dents it tubes to clear parts, burnt plug wires. I have never owned a car with headers, so I have to go with what I read. I do understand that some problems with headers are self inflicted by poor quality and poor installation, which would not be a problem for me. But, I also am tired of making decisions based on race-boy hype and marketing. And then you start getting the comments that are off based and nothing more than bravado and ego issues about who has the biggest.....!

 

Can you tell me what is Bubba about the extensive reports of excess heat near their feet when using headers. There was a 300 plus posting awhile back on trying to insulate it, without success. I drove my car for two years before taking it down, with stock L48 and 2 inch manifold, and never felt any excess heat in the car.

Look, please don't misinterpret my posting. I am listening, and considering the idea of headers, but I find myself always resisting improvements that have more place on a race track than a fun to drive street car. And last thing I want to do is make a change that introduces problems for something I do not need. All the components I have bought so far are about making a durable, reliable solid engine and car, with Made in USA parts. It sucks the ZZ4 short block was made in Mexico, and my only consolation was it was made by GM.

 

So on one hand Race boy comments you can identify , but Bubba comments on headers you take as gospel ? Anyway ...

I admire your desire to get the best with what you have , I suggest sending that short block back , getting a full motor and bolting it in. My 1980 had that done prior to my buying it during its restoration.

It did have the center bolt covers , ran like a clock and still does to this day with ZZ430 clone top end on her.. That was how I bought it with the ram horns as your wanting to use. It drove perfect and had pretty good pep in her step.. Solid Solid set up you cant miss with it ..




And after the ZZ4 was upgraded

 

I am not going to send the shortblock back. I think my motor will be a better, more torquey motor than a ZZ4. I actually pushed myself with going with the 270 cam I bought, as I was really thinking about the 264. The power graphs I studied show more torque at lower RPM with the smaller cams, and most people agree with that.

Thanks for your comments.

 

I second the afr heads with 65cc chambers .alum heads dissipate heat better the a iron head ,so you can run a 1/2 point higher compression .what valve springs will you use ? have you bought any thing yet ? if not consider a 383 or 400 sbc short block .

 

I have already bought, painted and assembled (as much as possible) the parts on my list, EXCEPT for the heads. I have the 70cc Profiler heads ordered, but now almost at four weeks waiting. And that is why I am thinking about AFR's, as I can have them in two days.

If I order the AFR's, the 9016 heads they sell claim to have springs (L98 style single springs) that handle "most hydraulic roller cams". Maybe I should call AFR to make sure their springs would handle the Comp XR270HR cam before just assuming that.??

 

As far as headers go, a good compromise might be a set of block-hugger headers. I have been using the block-hugger headers that came with my Corvette Central exhaust system for about 4 years now, haven't had a single problem with them. They are lighter than the cast iron manifolds, and flow better, too. Just something to think about.

Scott

 

Are you referring to the Patriot headers and Magnaflow system?

 

I would look into beehive springs and maybe use 1.6 rockers on your intake. With the AFR's you should be very happy with the results.

 

XEs usually have a pretty fast ramp as it is personally a fan of 1.5 rockers with them everyones different though

Prefer the AFR 180s. You can run less timing with them also the combustion chamber is very efficient. Youll like the combo. Dont even sweat 10:1. Figuring the DCRs and all is a good guide but I wouldnt get too hung up on it. Youll have a strong running car!

Contact AFR about the springs