I have a 80 L48 and I would like to install these heads. Already have a 2101 performer manifold and free flowing exhaust, no cat 3" pipe in place with cherry bomb vortex mufflers. I will also be adding a XE268H Comp Cam. Tell me this will perk up this 190 HP slug. Not looking for extreme HP, just don't to get smoked by a Honda Accord.

 

Camels Have Humps not bumps.


the 186 casting 2.02/1.6 were good heads 38 years ago. You are money ahead to invest in modern combustion chambers. Oh, and throw away that junk performer manifold.

 

What's wrong with the performer manifold? Your right about better more modern stuff available, but these bump hump heads should be an improvement over the stock smog heads.

 

They are not worth putting money into. They are 64 cc. so you get some gains in compression and valve size if they are 2.02.

the performer has such small runners that it will shut off a 350 motor at just over 5000 rpm.

 

I'm trying to keep all of this under the stock hood, hence the 2101. Shouldn't these heads with this cam work well together. The plan here is to keep the budget in check. I had a look at your machine, very nice, but I just want a weekend toy that goes somewhat better than it does. I have a 2003 Duramax that I take my fustrations out on on the track.

 

With the use of dropped base air cleaners you can get pretty tall manifolds under stock hood. IMO - any of the higher rpm rated dual planes is a better choice. Personally the weiand stealth is one of the best in that class.

in a sub 10-1 c/r motor the crane 272 with 1.6 rockers would be my choice

 

While the parts you have will not optimize the performance of your engine, they will significantly increase the engine's output and...for the 'money'...you will probably be satisfied with the results.

 

I love Camel Toe!!

 

You're on the right track in addressing performance gains by improving the heads. The downside to the old double hump heads is the potential need for extensive machine work. Before you invest in them, check to see if these things have been done or are needed:

Valve guides - look to see if bronze guides have been installed
Valve seats - look to see if hardened inserts have been installed
Surface - make sure there's no evidence of erosion and that all mating surfaces are flat. (You may need a shop to check flatness.)
Seals and Springs - unless you know these are new or relatively new, replace them. They're not all that expensive on these old heads and if you're doing a valve job anyway it's even cheaper.

This site is worth looking at: http://www.hotrod.com/howto/51058_cy...ild/index.html

Regarding the smaller combustion chamber and improved compression ratio: This is good news if you plan to change the cam. Use one of the on-line tools to calculate dynamic compression ratios and you can start to see how improved compression ratio will let you add more cam duration which in turn allows you to add more lift. It all starts with the heads.

All that being said, I agree with others here who have suggested new heads. Unless you don't need any machining, a good set of aluminum heads is probably a much better place to start.

 

Got a set of Patriot Performance 2181, to much work for the camel humps. I think these were a better way to go.

 

At your level of build the 186 heads and 268 cam is a real nice combo. Sure the new aluminum heads @ over $1000 will make more power(need to spend that for a decent set) but even the 1.94 valve 186 heads will put a smile on your face. They flow much better than a lot give them credit for and the port size is fine for a 5500 RPM 350. The ports on your performer intake are probably a perfect match to those heads. Well matched components are the key. The heads, intake, bottom end, cam and q-jet carb all sound nicely matched and will probably put you right at 300 hp. All your power will be in the street RPM range with great bottom end and midrange pulling hard past 5000 RPM, pretty much maintainance free and will stay together. With the l48 bottom end your rpm limited anyway (sub 5500). If you have a higher gear rear end, 3.08, your power will be where you want it for a nice street motor. Here is a kit that has the parts to build the heads except for the seals and gaskets. Don't need to worry about installing hardened seats. Might have to install guides.
http://cgi.ebay.com/ebaymotors/Stain...QQcmdZViewItem

 

I was going to suggest some vortex heads as they are hard to beat for the price, but it looks like you got the Patriot heads.

As to the intake. I had a 5.75" Victor Jr. intake (with a throttle body, not a carb) under the hood of my '76, L82 hood with a drop base air cleaner, I am guessing an Edelbrock Air gap would be a close fit with a drop base, but I would ask someone that has done it.

 

OOPS, typed the whole thing before I realized you bought the Patriots. Oh well, if anyone else is in this situation....

This is very similar to my combination. I have an Edelbrock Performer 2101 with 041 casting heads (same chambers as 186 heads, later casting), Comp Cams 268H cam and 2.5" rams horns with true 2.5" duals all the way back.

It's a very nice combination for the street and I am very happy now that it is done and built. I do have a few observations and lessons learned you might be interested in:

1. If the heads are not in good shape, you will easily spend more than they are worth in machining, that's a fact with these old units. I spent much more on my heads than a set of aluminum Brodix cost. But I now have nice cores with high quality components, and mine were fully ported when I got them.

2. Check the valve sizes. If they have the 2.02/1.60 valves, try and find out if they came from the factory with them. If not, have them checked to make wure the valves are not shrouded. This is a problem with these heads and if you don't enlarge the chamber in the correct spots, the 2.02 setups flow worse than the 1.94 setups.

3. Have the chambers cc'ed. These heads are old and could have been through a couple of machinings. Even though my chambers had been enlarged, after decking, the final cc vulume was 62cc, which is smaller than the advertised 64cc. You'll need accurate numbers to do correct static and dynamic compression calculations. Also, make sure you have the correct piston to deck measurements from your existing block, this will figure into your calcs as well.

4. Comp techs told me that they prefer a max of 9.5:1 SCR with the 268H. From my calcs, I figure that's to try and keep the DCR under 8 with iron heads. For my engine, I had to work all of the numbers backwards and compute the correct piston dish. I ended up with an exact 9.5:1 SCR and a 7.8:1 DCR when combined with a .015" thich steel shim head gasket for a quench of .041.

5. My intake ports matched perfectly with the Performer 2101 when used with a Fel-Pro 1404 intake manifold gasket. If you are using rams horn manifolds and are feeling adventurous, you can port match the heads to a Fel Pro 1444 exhaust manifold gasket, then go back and hog out the ports and runners on the rams horns to match as well. It's about 4 hrs of time to do the manifolds.

6. I can't agree more with 63mako, you are shooting for a balanced combination here, so take your time and get all of your calculations correct.

7. Don't think you can get it done in a weekend as there will be parts that will need to be ordered AFTER you make certain measurements along the way. Good example here is pushrods, after installing the cam and heads, you will need to use an adjustable pushrod length checker to make sure you get the correct rocker to valve contact patch area. With my combo, I need significantly longer pushrods. Correct valvetrain geometry will be your friend. Go fast and mess it up and you will be sorry.

8. Get the matching springs for the cam from COMP, in fact, I would suggest the whole kit that has the cam, lifters, springs, retainers, timing chain, etc. COMP will not warranty anything if you don't use their springs and lifters.

9. Take your time and really try to understand how everything interacts. Specifically, spend time on dynamic compression ratio and quench. These are two items you will find it almost impossible to correct if you have an issue. They need to be correct in your design to avoid issues. If you get these wrong, your motor might not be able to take all of the ignition it deserves for performance, and/or you might be forced to run some very expensive gas. I spent about a year re-doing my motor with a friend and it was an awesome experience. Use the forum, there are some great folks here who will help.

Good luck!

 

Don't let them burst your bubble Metalman If those heads don't need any money thrown at them and they are ready to go and you just need to pick up a cam I say go for it!!! Your not going to be running 12s in the 1/4 but I'll bet you will leave a nice set of racing strips on the pavement

 

I have the same cam installed as you are about to. However, I went for 64 cc performer heads, 1.52 roller tip rockers and an EPS manifold. On the 18th I'll visit the dyno and be able to give you some numbers on how this combo does. Would be nice for comparison, right?

 

I think you'll have a very nice runnin 350 - however for how long - seel below comment on XE. I had a smililar combo years back. If not aware, you have to have the hardened exhaust seats installed in those heads to run unleaded. The only think I didn't like about them was the lack of accessory holes tapped in the ends. I gave my old set to my friend who just re-worked them and put on a 350 in his 56 GMC. They're actually pretty capable heads. I used to have them on my '68 Camaro which ran mid 12s at the time.. You can make them work just fine. I've had a bad experience with the 268XE. If you do some research you'll see this cam had a way above avg. failure rate. Mine lasted about 5,000 miles before I started to see evidence of lobes flattening. If you haven't already purchased I'd recommend lookin around some more. Many others have been o.k. but I think you're rolling the dice on Comp Cam XE line. Comp cams hasn't really come truthful about it and as a result many are frustrated with them as a company over the deal. They did offer to send me a free one and I refused it - not worth the time to keep tearing down the engine.