Hey all,

I just purchased my first Corvette ('77 4spd car) and I'm digging into it. FYI - I bought this as a project car with it's end result to be a reliable cruiser for my wife and I. Performance is not a priority with this project, just a car that looks cool, is fun to drive and gets acceptable MPG given the car it is.

OK - my first project with this car is the heads. #3 intake valve is stuck open slightly. Compression / leakdown test was very good everywhere but this cylinder which is right at 20% below the other cylinders. I have visually confirmed a stuck valve.

I am looking at two options here: Please keep in mind I am trying to keep the cost low on this project - it's a budget build.

1) Rebuild the current heads which are a '68 327 head - nothing special. Small valve etc. If the springs and valves are OK and a valve job can be done without replacing them I'm guessing around $400 to do a simple rebuild - hot tank, check for cracks, new guides, valve job, seals. Sound about right to you? Always the risk of running into the unknown here - needs springs or valves replaced, cracked head etc.

2) Option #2 is these heads from summit. Little more money (about $200 or so) than a rebuild of mine. http://www.summitracing.com/parts/SUM-152123/

I see three main advantages to these summit heads. Larger valves (2.02), hardened seats for unleaded gas and the big bonus in my mind - they are 100% new from top to bottom including the head casting.

Am I off base here to consider the Summit heads over a rebuild of the ones I have? I think I know the answer to my question, but it's always smart to get other thoughts and opinions.

$600 total for two is a big chunk out of my car funds so I need to be smart about this and spend every $$ wisely.

Thanks for any advice guys,
Adam

 

First I would like to congratulate you on looking at iron heads. Most days now it's aluminum, then eat Piazza and Twinkies all winter and there goes you're weight advantage.

Summit buys from larger companies and put their name on the part but you can be pretty sure it's going to be a good part. You might need different pushrods depending on how your valve train positions your rockers over them valve stems.

Check your static compression with those head and then you dynamic compression which bring the cam into play, depending on the cam I would shoot for 9.5CR.

My original 355ci made 300RWHP and 333RWT with iron heads and near 10:1 compression ration. Do your homework first and buy the parts second

 

Hi Motorhead,

The bottom end will stay the way it is. I have solid oil pressure and unless I find to real need to replace it, will be keeping the stock cam - just doing the heads at this point. The current heads I have are just a 1.72 / 1.50 70cc so nothing special at all. Passenger car heads IMO.

The Summit heads are designed after the "double hump" head design. Same 72cc chambers I currently have. I'm thinking they would be a decent swap for me and since they use the 2.02 / 1.60 valves should be a slight improvement in performance. My goal here is reliability and to end up with a cruiser my wife and I can enjoy.

Given that they are 100% new parts, $310 each seems like a decent price to me... thoughts anyone?

Thanks for help,
Adam

 

In this context, anything that helps your engine breathe will be a good thing. You will notice the difference with the double humping heads.

Intake and headers are a nice compliment to those heads, since you have to pull them anyway.

 

The Summit heads would be a great upgrade.

 

The new heads will flow better than the current ones, limited by the cam profile. The current head's capability may be more than what the cam can do....so save the money and get the stock heads redone.

HOWEVER...if its the heads that are the limiting factor and not the cam...then you would be better getting the new heads which would should give a power increase by using all of the cam.

Are you for sure you know what the cam that is in there?

Or something else to think about...what are you plans in the future? Say you spend $400 on the stock heads.....a year from now perhaps something happens and the engine needs a rebuild or you get the ..."I need more power!!"....so you would be back where you are now...but $400 poor'er. See what I am getting at?

Of course all this depends upon the condition of the heads once apart. the decision may already be made. Guess you could also look at used heads, where someone got the ..."I need more power"....and you could pick-up a nice set of iron heads that you could bolt and go.

Let us know what you find out.

 

The car came with a new Edelbrock Performer intake and carb, headers and an Accel HEI coil. Nothing major, but they are all good parts that are aimed at a car like I want to end up with. Think they will be a good fit. I have considered a cam kit when I do the heads - still reading up and thinking on that.


Lanny - Agree and understand what you are saying. That is one of the reasons I'm leaning towards the Summit heads. I feel like the current heads are not worth sticking $$ into, and as you said if I do, I now have $$ into heads that are going to limit any upgrades I may want to do down the line.

I do not know what cam is in this (yet), but I will be checking into that when I pull the motor to seal it up and detail the engine compartment. From the smooth idle, I'm guessing it's a stock cam or if it is a replacement cam, it's a very mild one.

Tim - I think they would be as well - still doing research before I fork out my hard earned $$.

Thank you gentlemen - you have confirmed what I was thinking

Adam

 

I wouldn't put a nickel into any C3 head, they are all old school, any new head out there will out flow them out of the box, so as soon as he wants more power the heads are there, now for a cam.

If you do this, do these heads come in 64cc ? Also there is a very thin steel shim gasket I used. I can get you the part number made buy Federal Mogul so in the future all he has to do is change the cam and put the steel shim gasket in and he's in for some tire smokin fun

 

I called yesterday to get more detailed info on the Summit heads and they are only available with 72cc chambers. I understand the advantage of the 64's, but that's not my goal with this car. As long as it runs well and we can enjoy cruises around town and into the mountains from time to time, I'm good with it.

Spending my day tracking some of the wiring "tricks" that have been done to this car over the years. Some people should not be allowed to own tools.

 

Your 77 has dished pistons so 64cc wouldn't even require super unleaded.

one point of compression is worth like 6% gain at all rpm

 

Don't "over think" your project or you'll either way over spend or just throw in the towel and forget the whole thing.
Buy the Summit heads and a good Felpro head gaskets and put it all togather and you will be happy.
I put togather 72 Monte Carlo with a 350 with a real set of factory 375 horse heads and just a performer cam, aluminum intake and headers and it was the smoothest "king of the road" engine I have ever had.

 

Take a look at a set of these instead:

http://www.summitracing.com/parts/NAL-12558060/

For the same money, a set of Vortec heads will blow away the older style heads. These have 64 cc chambers too. You could also scavenge the local wrecking yeards for a set of these for probably $150 or so for a pair.

You will need a vortec specific intake to use them though.

 

Yeah, you need a new intake, and the old perimeter valvecovers won't fit, so you need some center bolt valve covers. And your old rocker arms won't work, either, you will need self aligning ones. This is all going to cost close to 300 bucks or so, maybe 200 if you find some bargains.

If you can get away with spending 400 bucks on your existing heads, (and that's a fairly big if) you will still be left with a nice, fresh set of crappy flowing old-skool heads.

The Summit heads sound like the way to go for what you are looking for.


Scott

 

if the vortec heads look good try researching the iron eagle heads they are available many ways. i agree about smaller chambers the extra compression will help more than the valve size in this case

 

Vortec heads suck and all the parts you have to buy to make them work does to.
Whats the difference in reworking the old heads or spending $150 for vortecs and reworking them and spending all that money for the extra parts to fit the engine.
Then later down the road you want to upgrade again and you have to buy all new stuff for regular set of heads you should have bought in the first place.
I never was a fan of vortecs because they are limited to 450 lift with out machine work and all the other parts that only fit that head.
Buy the Summit heads you first looked at and get the job done and drive!

 

Tim H is about as subtle as a pipe bomb in a bucket of oatmeal, but he calls 'em like he sees 'em.


Scott

 

Engine Quest makes a 167cc and 180cc head, both have better flow than a Vortec head and way better than the Dart/World 165 copy. Both can be had for close to the same price without the swap problems of a Vortec. They also make a 200cc head that is a little more performance oriented and would suit a hotter 350/383 build for the future. The 200cc head seems to be comparable to the Iron Eagle Platinum in 200cc.

 

You sound as if your throwing roses at my performance and I will now take a bow!!!!!!

 

If you want to keep in your budget and are not concerned about increasing power significantly, consider a set of rebuilt heads from your local Advance Auto/Autozone. I purchased a pair of 76cc, 882 heads that were upgraded with 2.05 intake and 1.60 exhaust valves (all new moving parts) and 3-angle valve cut. Back when I did the swap from my anemic 624 heads, I paid approx $150/head. Again, they will flow a bit better given the larger valves. I had to trade my 624's in... no great loss. The rebuilt's also were cleaned thoroughly and resurfaced/decked so I probably had a little better compression (74-75cc chambers).

The valve sizes you describe don't sound right for a '68 327. I didn't know the heads were offered with such small valves... sound more like 305 heads from a late 70's, early 80's mouse motor.

After the swap, I was chasing horsepower and upgraded (again) to a pair of DART Iron Eagle 72cc chamber, 180cc intake runner heads that flow much better without any porting. I spent under $1,000 for the pair and I know prices such as what you are considering paying for the Summit heads are much lower now.

Shop around, do your homework and don't be afraid of buying good rebuilt parts.

Remember also, you can have that distributor recurved (if it hasn't been already) and pick up 50hp. Why? Because the stock curve does not begin to take advantage of the intake, headers, cam, exhaust that you have (even the stock cam). Also, have the carb looked at/rebuilt. Is it the original qjet? They REALLY respond to a nice refresh and re-jet. Lars did mine for under $200 (delivered) and I've not had to touch it since (over 11 years and counting).

If you decide to swap the cam out, you can get a very nice cam from the Crane Energizer line that will put that engine in the power band it was built for without sacrificing MPG's or emissions. I have the 272H; a single-pattern .454/.454 max lift cam. With lifters, it is under $150. VERY peppy and wakens the engine considerably.

 

Hi Ted,

Thanks for the ideas I've been looking around and the prices at Auto Zone, Checker (sell the same heads as each other with different names) are $256 each, but I would talk to them and get more details before I order anything. Napa also sells rebuilt heads which show a price of $309 - I'm guessing that includes a core charge. They all seem to be about the same price.

The Summit heads are $309 each as well, but this balances out if you consider they don't take core returns, which also leaves me with a set of heads laying around that have a stuck valve and won't be worth much.

I'm going to call a local machine shop this morning - I (somewhat) know the owner and they have a good rep here locally. Maybe he has a set of 350 heads which I could exchange mine for and get a fair price.

Thanks again for the ideas - I didn't even think about the local parts stores as an option.

Adam