which cyl heads/cam?

[77D-VeTTe]

I'm looking to get some mo' go go out of the momo (-ter)
8.2 compression

plan:
headers- Hooker SC or Dynomax
intake- Edelbrock Performer RPM
carb- Edelbrock 600 or 750cfm
cam/heads-???

my goal:
streetable potent power for daily driver. 300+hp range. Id like to not break the bank on heads. maybe GM vortec, World, or Dart heads??? Strong cam but not too much of a crazy idle or too hard on the mileage.

Any thoughts, sugestions, concclusions, theories, promises, provocations, afirmations, allusions, or ideas? :s

-D
'77 coupe M4
4.10's
true dual exhaust w/ flowmaster mufflers
and a new clutch

 

[69MyWay]

You are going to get the biggest bang for you overall buck on the heads. So, save up, postpone the project or whatever you must do to get the heads you want first.

I would strongly suggest the Edelbrock aluminum small block heads. By bolting on the 64CC combustion chambers you will get that engine into the 9 points plus range of compression. Beleive or not, Edelbrock builds and test most motors in the 9.5:1 compression range. This is a great place for a street engine to live.

You can get the heads and hardware to boot for around $1,200 (heads, head bolts, gaskets, push rods/have to be hardened to pass through the push rod guides).

Now, you are talking about an easy 75-85 hsp gain if you were to put all the stock intake and exhaust components back on! You can't get that out of a cam and intake alone.

So, if you go the extra mile and drop the cam, intake, carb, and tune it right you can easily hit 425 street hsp out of that same short block! Plus, the ewwww and ahhhhhhh you will get when you pop the hood and people see those schweeeeeet aluminum heads on there will be worth half of the purchase price.

The problem is that the stock 77 heads are horrible on just about every thing about them. Pressed in studs, small valves, large poor designed combustion chambers, and small runners. You may actually go slower in cerntain RPM bands and loose hsp with a larger cam, intake, headers, etc. and those same heads. Plus, the old tired valve spring and retainers my let go leaving you looking for a complete new engine after a valve rockets through a piston.

Hey, just my .02 and your $1,200!!!

 

[77D-VeTTe]

Thanks for replying, I did more research on heads and found that the vortech weren't what I was looking for so I'll pay a lil more and get the Edelbrock 64cc heads. I swaped a Edelbrock carb adn performer intake on her today, much better than the tired old crap-a-jet and iron intake. Thanks again for the advice
400hp here I come... in a few paychecks that is hehe

your .02 is expensive

 

[cmegga]

Edelbrock also has some new aluminum head out. the e-tec series. they are going for 999. and i have heard alot of good things about them... another option to consider

 

[JHL]

Edelbrock also recommend hardened and ground flat washers as well to spread the load when you torque the heads. The part number they gave for the bolts which need to be slightly longer to accomodete the washers turned out to be an ARP bolt set.

If you do decide to go with Edelbrock heads you won`t be disappointed, the quality is excellent and with a cam they really add some HP. As 69 said 400hp is easily within reach. After adding their cam and heads to my engine I knocked a full second off my 1/4 mile time even with a slipping clutch. I`m hoping for at least another half a second this summer with the new clutch in.

J.

 

[69MyWay]

JHL,

Did you find it a little tricky to center up the rocker arms on the valve tip when having to set the position of the push rod guides?

Try as I may, I could never get the tip of the roller rocker to sit dead center of the valve stem from front to back. Side to side I did get the roller to strike the middle by getting a custom length push rod.

 

[JHL]

69

Yes I had the same problem, I fiddled around for ages trying to line everything up and eventually gave up. The problem as far as I could see if you look from the side of the engine is that the valve is not on the same centerline as the pushrods. I bought a set of Crane stepped guide plates to replace the original flat ones that came with the heads and they were a bit better. By moving the plates around I thought it would cause the pushrod to be moving up and down at a slight angle instead of perpindicular to the lifter and upsetting the valve train geometry so I tried to keep mine as straight as possible and set the rockers at a bit of an angle across the head.

One solution, albeit a very expensive one, is shaft or maybe you might say rail mounted offset rockers. Jesel make a nice set. I saw them on a smallblock that was in a drag car the last time I was at the strip. The seat for the push rod is off center on the rocker and the roller lines up perfectly on the valve. It looks odd but sorts out the alignment problem. They guy said they cost him about £850 + tax. Twelve hundred bucks in your money !!!! Alternatively I was tempted to try it without the guide plates but this might damage the heads.

May be someone with a bit more technical understanding could shed some light on this subject. I have never noticed this before but this is the first set of roller rockers I have bought and I also wondered if the position of the valves in the Edelbrock heads was identical to the Chevy original equipment. It seems odd that the the valve and pushrod are not on the same centerline.

J.

 

[69MyWay]

Here are two pics of my rocker/valve stem alignment. I, like you fought this for a long time and eventually settled with this. This engine has a little over 3 thousand miles and has seen plenty of red line bursts.

 

[69MyWay]

Here is the other angle. I guess this is the one most paid attention to, as it is where the roller strikes the stem. The goal is to adjust the length of the hardened push rod to get the roller to hit the center of the stem most of the time.

 

[75SHARK]

Not loosing site of orig subject, I think 69 myway has given real sound advise. Definitely spend the bucks in the right direction here, not the place to skimp! You'll save weight with alum heads, and many manufacturers are making 'CNC ported' heads. It's also known that you can run about one compression point higher with alum vs. cast iron. As stated, some companys are selling tested/proven combinations. That takes so much guess work out of the decision. Vortec is a good head, but following purchase I would want to have them ported and messaged. So right there we're almost $700-$800 out the door w/tax. Then there's the dedicated Vortec intake manifold, more $$$. Yep, my vote's for todays alum heads! Flow characteristics are way beyond yesterdays best!
Best of Luck -Dave

 

[77D-VeTTe]

the valve and pushrod not on the same centerline worries me, are there any other cyl heads I should consider?

JHL-- why did you go with shorty headers instead of full length?

Thanks,
-D

 

[JHL]

77D-Vette

This is not just with the Edelbrock heads, I had a look and it is the same in the original Chevy heads. I have an old Chevy Power Catalog with a lot of good drawings and pictures, it shows several combinations and a couple of pictures with offset rocker arms on standard heads. There are numerous heads to choose from some undoubtedly better than others, AFR`s matched with a Comp cam is another popular choice, I like the Edelbrock`s and have been using their parts on cars for years without any problems. They offer tried and tested packages.

The shorty headers were on the car when I bought it. I was going to buy headers when I built the engine but was a bit concerned about ground clearance with big collectors under the car and then having to have a custom exhaust made. I think CA cars had them in 80` and all vettes in 81 had them fitted as standard.

69

Great pictures, I stuck with the original pushrod length and made the best of what I had. Like yours, my engine has seen plenty redline hits and I`ve had no problems so far.

J.

 

[Ganey]

You do need heads & badly need more cam ! A Comp Cams XE262 will put you well over 300 w/ good ex.!

 

[Roy]

More "Go" for 77D-Vette

I think this thread started with 77D-Vette looking for a street worthy 300+ HP set-up using his 8.2 CR bottom end... all at a reasonable price. Here's my recommendations in the order that I would recommend adding them on.

1. Rebuild the stock Quadrajet carb.

Excellent carb once you learn how it works. Cost: $40. After further modifications are done, you may want to re-jet the Q-jet.

2. Replace Old Spark Plug Wires.

If the plug wires are 5 years or 50,000 miles old, replace them with good quality (MSD 8.5mm Red) plug wires. Cost: $40.

3. Repair all vacuum leaks.

There is no sense spending money on an engine that has old, cracked and leaking vacuum hoses as it will never run strong. Take the time to replace any vacuum hoses that are 15 years or 100,000 miles old. Cost: $20.

4. Install a free flowing air filter.

You can buy Edelbrock air cleaners all day long on E-Bay for $20.

5. Install an Edelbrock Performer Intake Manifold.

You already have freer breathing mufflers installed, so helping improve the intake would be a logical step. Cost: $140.

6. Install a Hedman "Tight Tubes" set of shorty headers.

Minimal alteration to existing exhaust system. Good fit and maintains stock ground clearance that the long headers take away. Cost: $200.

O.K., at this point you have spent around $500. Stock output on the 77 L48 was around 180 HP and 210 on the L82. With the above modifications, you would be luckey to see a 20 HP increase but your car would have more pep, be very driveable and not break the bank. Beyond this point, open you wallet.

7. Install an Edelbrock Performer cam.

Easy enough to do slowly over the weekend and it is not rocket science. The Performer cam pulls from idle to 5,500 RPM and is very streetable. Change the timing chain while you are inside the front engine cover. Cost: $150.

8. Think about Edelbrock 64cc aluminum heads.

While you have the intake manifold or the timing chain off, you should ask yourself if it is time to bite the big one and purchase a pair of Edelbrock 64cc aluminum heads. Don't jump into this before considering all the pros and cons.

The first "con" is cost. I buy new Edelbrock 64cc heads from a Chevrolet dealer for $900 a pair, which is $75 over dealer cost. You should be able to find a new pair for $950 on the Net. Yes, you will also need hardened push rods that are 1/10" longer than stock. Add $45 to $85 for push rods. A complete FelPro engine gasket set at $28 is cheaper than buying individual gaskets. Engine bolts ... add another $25 blah, blah, blah and you end up with $1,100 or so.

The second "con" is your bottom end. If your bottom end has not had a quality rebuild in the past 25,000 miles, increasing compression on the top end will create problems with your bottom end. You can add minor upgrades such as Items 1-6 above, but once you increase compression on a worn set of piston rings, rod bearings, and poorly balanced connecting rods, you are pressing your luck and your bottom end. Remember, low compression hides allot of imperfections in the engine and they run smoother than high compression engines. With increased compression, expect ring blow by, increased oil consumption and a rougher running engine. To avoid these problems, dig into your wallet and spend $1,000 to remove your engine and have it rebuilt by a quality engine machine shop.

The obvious "pro" for the 64cc heads are less weight and added performance, but only if you do things right... that is, do Items 1-7 and if you decide to install 64cc heads, keep going and complete the job on the bottom end. So total cost for heads and bottom end work = $2,100 plus $650 for Items 1-7 and your total so far is $2,750 and that's allot of money to spend when you can buy complete new Chevy 330 HP engines for $3,400.

Some folks bad mouth the stock cast iron heads, but the aluminum heads really don't perform that much better than stock heads, especially if you have a little work done to them by a quality machine shop. You can port and polish a little, install larger valves and mill the heads to bump compression a little or allot. The big advantage of the aluminum heads is the weight savings. Used Corvette cast iron heads are easy and cheap ($50/pair) to find and you can work on a replacement set while your original heads are still installed on your engine. I have a good pair of extra heads that allows me to "play" with them when I feel like it and have them ready for the next project.

And speaking of HP, even with all of the parts and modifications listed above, do not expect to get more than 300 HP to 325 HP from your modified engine. Owners always talk about breaking the 400 HP mark, but to do so is cost prohibitive and a waste of money, plus you will sacrifice all around driveability. Don't get me wrong, I enjoy making these modifications for fun, but I do realize that anything beyond a certain point is wasted money that I will never recover and the easy going nature of the 350 engine is compromised.

For your needs, I would recommend sticking with the basics of Items 1-6 and spend your time driving the car rather than working on it.

 

[77D-VeTTe]

Thanks for the input Roy. Here is where I stand in your outline.

1. put Edelbrock 600 on, Quadrajets give me nightmares...
the edelbrock has always been reliable to me, every Quad I have had kept comming up with problems.

2. plug wires are in good shape, but some new sparkplugs are in order.

3. most of the vacuum lines look pretty good, I did notice that the headlamp vacuum lines by pass the vacuum canister up front. I'll have to get into that this weekend.

4. K&N airfilter

5. just did that too, Performer Manifold

6. Headers are on my list to do. Hedman, Hooker, or Dynomax.

7. I was talking to a friend the other day that is a mechanic and he was almost positive there was a performance cam in it by listening to the way it was idling. we adjusted the carb and the timing and looked for vacuum leaks and didnt find any. Im going to call the previous owner and find out if he had a cam installed. Come to think of it when I put carb and intake manifold on I had trouble getting a smooth idle. I guess it could be a hidden vacuum leak?!?!?!

8. obviously not yet, leaning towards Edelbrock 64cc, or maybe trickflow.


-D

 

[Ganey]

Naturally the engine needs to be in good condition.
Don't even think about the Edelbrock Performer 350 cam, would put more cam in a girl's stock auto. You want a min. Comp Cams 268H or XE262. Go w/ Dynomax coated headers. This will easily outrun all the other mods mentioned combined!

 

[77D-VeTTe]

Bubba was tuning my carbuerator!!! turns out the "cam sound" was lack of adjusting BOTH fuel mix screws on the edelbrock 600. HEHE
I agree the performer cam isnt much. I have heard very good things about the high energy and Xtreme energy cams. vroom vroom

Thanks everyone for your input.
--D

'77 4spd
4.10's,performer intake+carb,dual exh. w/flow. mufflers

 

[JHL]

Ganey,

I have read lots of good comments about the two Comp Cams you mention. The 268 had better low down torque than the RPM cam which in a heavy auto Vette would probably be the better choice for a daily driver. My car is a 4 speed and pulls over 3000rpm@65mph so I assume about a 3:70 rear end and can cope with the RPM cam which has a little bit better top end power. I know of a couple of cars running in the 12`s using RPM cams.

On the Edelbrock site they have a dyno graph showing 420hp with 9.5cr using the slightly larger 70cc RPM heads, admittedly this give no clues as to the drivabilty in a car and Edelbrock do not recommend it for "heavy" cars. I liked the idea of the known quantity the Edelbrock kit gives. Buy all the bits listed on the build sheet, put it together as per the included instructions and within reason you should be close to their numbers. I have no reason to doubt that the lower end Performer set up should give equally close results and around the 300 or so hp they say. Another set-up I looked at was Holley`s Systemax kit, again an advertised horsepower rating with out to much of the guesswork.

I see these kits as being ideal for the guy who likes the idea of building their own engine but maybe doesn`t have the techinical knowlege of a race engine builder. For those that just want an engine with a decent amount of power and not the dirty finger nails then as suggested previously they should look no further than the local Chevy dealer for a crate motor, but wheres the fun in that.

 

[barrier5]

In case your interested I was browsing Ebay looking for seat covers and theres a set of 58cc alum chev heads for sale they claim are new.
p.s. there not mine