• Skip to primary navigation
  • Skip to main content
  • Skip to primary sidebar
Quarter Mile Addiction

Quarter Mile Addiction

Drag Racing T Shirts, Parts & Accessories

  • Home
  • About Us
  • Contact Us
  • Privacy Policy
  • Terms and Conditions
  • Return Policy

Mopar LA Cylinder Heads High Performance Bolt On Upgrade

Bolt on a pair of aftermarket small block Mopar LA cylinder heads from Edelbrock and you’ll notice the difference in power and performance without a doubt. With a few more simple bolt on parts as such as a camshaft swap, long tube headers, 4bbl carburettor, intake manifold, and roller rockers you can easily gain 100+ RWHP (150+ hp at the crank) over your current stock series v8 engine.

To find out what your current factory stock 318, 340 and 360 LA series engine made view the horsepower chart listed on the Allpar website here  https://www.allpar.com/mopar/318

No need to port your existing heads, swap out your pistons for high compression ones or even have your old heads milled for more compression. Simply make these few changes and run on premium 93 pump gas and call it a day. Follow along to find out exactly what to do. This can all be done without even pulling your engine from your car. You can even do it yourself if you wanted to.

Chrysler LA small block v8 engine

Mopar LA Cylinder Heads Flow Chart Stock VS Edlebrock RPM

First we’ll take a quick look at how this is possible. We’ve borrowed a couple of flow charts from the Hughes Engines website. You can see the charts here along with many other Mopar heads flow charts, as well for future reference and research. http://www.hughesengines.com/TechArticles/1headflowchartscomparisons.php

Mopar LA heads cylinder flow chart

We need to take into consideration that all things are not completely equal. Depending on the year of heads you have on your small block LA engine, the intake valves sizes were typically any where from 1.78 up to 1.88 inches in size. Only the 340 LA engines had the 2.02 intake valve sizes. You can see the chart here for more info on stock valve sizes from the Engine Labs website. https://www.enginelabs.com/engine-tech/

You can see from the description in the image above as to what heads Hughes Engines are referencing to. You’ll notice the ‘Stealth’ head porting service includes adding the larger 2.02 intake valves. Even so, if we take a look at the highlighted flow numbers in the above chart, the Stealth mod flows 218 CFM on the intake side. This is significant of course. When you consider the money you’d have to invest to have this done on your factory heads, you’d be spending the same money if not more than the cost of a new set of heads.

Now let’s take a look at the Edelbrock RPM LA heads flow chart from the Hughes Engines website.

Edelbrock LA cylinder heads flow chart

As you can see the highlighted numbers show 249CFM with the Edelbrock aluminum cylinder heads. They are  not ported. You’ll also notice I’ve only focused on the .550 inch lift numbers. Edelbrock recommends the heads are suitable for camshafts of up to .575 lift.

When considering a higher lift setup it would be wise to consult either your engine builder, if you’re not doing the install your self, or contacting Hughes Engines via their website. Just to be sure you’re making the right choices to achieve maximum potential and that the setup will last.

With a 1.6 roller rocker ratio and depending on your cam of choice, you’d be heading into .600+ valve lift territory. If your using your factory 1.5 ratio hydraulic rockers, and want higher lift, make sure you do your due diligence first. Obviously when getting into the top end of the valve lift scale, you’re heading into 400+ horsepower in stock form with the performer RPM heads! If you’re building a killer street/strip engine then I’m sure you can see the potential here.

Cast Iron LA Heads Horsepower Numbers!

Ok so now that we have got the basic technical aspect out of the way, as far as the performer RPM heads go, let’s see some proof. I’ve included a video here put together by Richard Holdener. You’ve probably seen a lot of cool videos by Richard already. Perhaps you’ve seen this video before too.

The engine featured here is a 360 2bbl LA series engine. The heads used throughout the dyno test are the stock factory cast iron heads. Richard does give the heads a very mild port job. You’ll see all parts I’ve mentioned at the start of this article have been used as well. Including two different camshafts.

I wanted to highlight the potential that your stock cast iron heads do have. So if emissions testing in your state, city or country is an issue to overcome, fear not. The stock heads still perform very well. While watching the video though, consider what you have learned here, as far as the potential of what the Eddy heads have in them. Bolting on a pair of new Edelbrock heads is like bolting on a pair of ported big valve heads, but better.

Edelbrock LA Heads Product Description

A few features the aluminum Edelbrock Mopar LA cylinder heads have include

  • Phospher-bronze valve guides
  • Interlocking ductile valve seat (hardened and replaceable)
  • Stainless steel high flow 2.02 inch intake and 1.60 inch exhaust valves
  • 63cc combustion chamber
  • 171cc intake ports
  • Heat treated and machined steel retainers and valve locks
  • Heavy duty valve springs suitable for up to .575 inch valve lift. For higher valve lift, more suitable springs are recommended.
  • Stock location intake and exhaust bolt holes and flanges
  • Stock spark plug location

You can use your stock cast iron intake manifold and exhaust if need be. Headers are recommended for better exhaust flow and increased horsepower. Better economy can also be achieved. Your stock valve covers can also be used.

Harland Sharp roller rockers for small block LA heads

As mentioned already, you can use your stock rocker assembly. You can also use your push rods as well. As long as they are inspected for any wear and measured for the correct length. Some after market heads require the use of roller rockers, as your stock rocker gear won’t fit on those particular heads.

Although this leads to an increase in horsepower too, this is an added expense when looking to purchase and install new heads for your engine. You can also use roller rockers on the RPM heads too. Perhaps the initial budget for roller rockers might be better spent on other recommended parts as such as upgrading to a better performing camshaft.

If you are upgrading the camshaft, look to buy the complete package. This will include the tappets or lifters, push rods, timing chain and timing gear.

Small Block Mopar LA Heads Conclusion

If 400+ plus horsepower is your goal for your Dodge 360 engine or your 318, as you’ve read and watched from the above video, this can be achieved on a budget. Simply bolting on the aftermarket heads after having them checked over will net you a good noticeable increase in power and performance too. Even if you kept with the 2bbl intake manifold and switched to a Holley 350 2bbl carburetor. Or the stock carburetor.

How much more you would gain will vary. As long as you have good compression, or as good as can be expected you will notice the difference on the street or highway. Remember in the video Richard says the stock compression in his 360 2bbl LA engine had about 8.2 to 1. I had to laugh a bit when he removed the stock air cleaner from the engine and made 5+ horsepower right off the bat! Switching to a K & N open style filter would bring similar or close results.

This was good to see right at the start. Then changing out the parts and testing on the dyno, we were shown increased results. A quick re-cap on the parts swap were:

  1. Two different induction systems
  2. Long tube headers
  3. Two different camshafts
  4. Ported heads
  5. Changed from the 2bbl carburetor to a 650 Demon carby along with the bigger camshaft for the biggest horsepower gains

With the smaller camshaft and Quadra-jet carburetor installed, the engine was put back into Richard’s van. This was then put onto a chassis dyno where we saw an increase of 100 horsepower at the rear wheels over the factory stock 2bbl setup. As shown in the video.

So it really comes down to, ‘how far do you want to go?’ and what realistically fits your budget. Many of us tend to buy one item at a time and piece things together over time. On the other hand installing the new heads first allows you to keep driving the car, or truck or what have you, even if that means sticking with everything else you currently have for now.

My goal here is to show you what’s doable. It is relatively simple. At the very least you now have some basic knowledge that allows you to ask the right questions, when looking into purchasing some new heads for your beloved Mopar.

If you have any questions fell free to leave a comment below this article. If you’re interested in purchasing a new set of RPM heads for your small block LA engine, you might be interested in reading my review including the pros and cons of the Edelbrock aftermarket Mopar LA cylinder heads. You can find that info right here https://quartermileaddiction.com/best-small-block-mopar-heads-on-a-budget-build-review/

Reader Interactions

Comments

  1. Art Phelan says

    January 26, 2021 at 1:20 pm

    Okay everything sounds good, you mention fuel pump, carb, heads linkage, regulator and so on. What I’m trying to do if posable through guys is make reliable 500 to 550 HP .
    And this will be going in a 1966 Dart GT with a 69 340. can you help me do this and approximate price range .
    Thank you much Art P

    Reply
    • Dave says

      January 26, 2021 at 5:35 pm

      Hi Art thank you for your question.

      To make 500 to 550hp you’ll need a good top end package. You can find more info on this page here https://quartermileaddiction.com/buy-edelbrock-top-end-kits-1967-1991-small-block-chrysler/

      I’d also recommend a stroker kit as well. Mancini racing has many kits to choose from. You can buy a kit for around 2k depending on which option you choose. Here’s a link to their website for quick reference https://www.manciniracing.com/smblstroas.html

      There are many stroker and top end kits available. All are very similar in performance and vary in price. I hope this answers your question. All the best. Feel free to let me know how you get on.

      I also want to add an alternative to a stroker kit. Another option would be to bolt on a blower. If your current engine is still in the car or a complete running engine this is a viable option. You can still use your stock bottom end. Add the heads, use your stock 4 bbl intake and go from there.

      I’d opt for a blower spec camshaft, port match the intake and headers to the heads. Make sure you can provide more fuel than you will ever need. With 5 to 7lbs boost you’d be in the 450 to 550hp range with loads of torque. All under the hood.

      You’d be in for similar money with a stroker kit. By the time you tear down the engine, have it hot tanked and inspected for cracks, along with machining a supercharger kit is another viable option for the money. You can find more info at this link here https://quartermileaddiction.com/small-block-mopar-supercharger-kit-dart-cuda-a-body-bolt-on/

      Good luck. Either way that little GT is going to be a real hot ticket on the street no doubt about it.

      Dave

      Reply

Leave a Reply Cancel reply

Your email address will not be published.

Primary Sidebar

Drag Racing T Shirts

  • Drag Racing Hoodies, Sweatshirts, Clothing & Apparel
  • Unique Drag Racing Polo Shirts | Quarter Mile Addiction
  • Drag Racing Sweatshirts, Clothing & Accessories
  • Shop Unique Drag Racing Dress Shirt Designs Online
  • Custom Drag Racing T Shirt Designs – Vintage 60s & 70s Mantra

Drag Racing Parts

  • Best Small Block Mopar Heads | On A Budget Build Review
  • Small Block Mopar Heads For Sale & Tech Tips For Your Swap
  • Mopar LA Cylinder Heads High Performance Bolt On Upgrade
  • Cylinder Head Porting Secrets Dodge 360 LA Engine Templates
  • Buy Edelbrock Top End kits 1967 – 1991 Small Block Chrysler
  • Small Block Mopar Rockers Edelbrock LA 360 Dodge Engine

Supercharger Kit

  • Big Block Mopar Supercharger Kit 440 Dodge Carburetted V8
  • Small Block Mopar Supercharger Kit Dart ‘Cuda A Body Bolt On
  • Supercharger Kit For Dodge Ford & Chev. Bolt On More Power
  • What Is A Supercharger Kit? Roots, Twin Screw & Centrifugal

Drag Racing

  • Drag Racing T Shirts Long Live Nostalgia Drag Racing
  • What Are Drag Racing Classes? USA, CA, UK, AUS & NZ

Drag Racing Apparel

https://www.youtube.com/watch?v=jsnEOWri6Y4

Terms and Conditions - Privacy Policy