well not trying to hijack your thread but I am actually selling a set of cnc scrogy dickens ls3 heads that have been proven to make 30rwhp or more, I have then with brand new high lift duel springs arleady installed also and these are brand new heads, if your in the market for heads still and intererested shoot me a PM. im selling my heads at a very low price compared to the heads new.

 

Well, unless Reher-Morrison has a new kind of port devlopment, I don't see them making anymore power then any other comparable LS3 heads.

When the test was done on all other rect. port LS3 heads they all made around the same horsepower so I don't see this head being much different.

 

it's common knowledge that Reher Morrison are the Holy Grail when it comes to anything to do with Chevy engines.
They were world champion Pro Stockers from way back in the late 70's and 80's when they would have to take a block of aluminum and make world champion heads out of them.
No way no how is any of these places better than them at Chevy porting heads.

 

 

Reher-Morrison = GOOD
Everyone else = CAUGHT UP
I don't think R-M is quite as holy as they used to be...

 

7 years and 11 days later, we have someone chiming in how great RM is. What took so long?

They are good, but there's only so much you can do with an OEM casting. I'd say most porters are going to provide similar results, unless they butchered the heads or a LS3 head does not align with the intended purpose.

 

My 99 TA has a 416 with Reher-Morrison heads & cam that Darin Morgan spec'd for my daily driver goals. Darin developed the program using wet flow bench, dry flow bench, dyno testing and many other methods. The intake port sounds smooth and clean on the flow bench and doesn't stall. The intake port is capable of clean air flow all the way to 1 inch of cam lift. Yes 1.000 cam lift. Depending on cam selection, tuning, dyno and supporting mod's 500whp-550whp is typical with LS7 lifters and hydraulic cams. More is possible with low lash solid roller or full solid roller cams and solid lifters etc.

The great thing about working with Darin and Reher-Morrison is they don't try to sell you stuff you don't need just to be selling it. They also help you work within your budget to reach your goals.

My budget was exhausted getting my 416 engine fixed afternoon the TA was stolen so I had to pass on the low lash solid roller set up and mid runner Fast intake when the set up was repaired. Reher-Morrison customer service and support was excellent after the sale and in helping me get the heads repaired in a timely manner.

Pictures and details of Reher-Morrison LS3 heads in 416 build

Here are my flow testing results on a very conservative flow bench. The specialist doing the testing said after the test and checking the heads they were 720+ flywheel capable with the right motor.




99 Black Bird T/A's 416 Dyno Results - RM heads

I would buy Darin's LS3 heads & cam again. My 416 made 517 whp & 471 wtq, 400wtq at 2,800 rpm

I think my exhaust set up on the 99 TA hurt whp a bit on the top end. On the plus side ground clearance is outstanding for a lowered car. Likewise, with more budget a better fuel system would have been nice, along with a low lash solid roller set up.

Reher-Morrison - highly recommended.

 

not to down your build. It's very nice! But I was able to put down 507 rwhp with my 416ci with stock 243 heads and a fast 102. With a medium sized cam . I went to aftermarket heads and now makes 580 rwhp on a loaded dyno . I think there are better CNC heads for the money. But I think I for your average guy most cncd ls3 heads will do the trick.

 

Mavn, sounds like you have a very sweet set up.

I need to make a few tweaks to mine in the spring and see if there are some lost horses to be found.

 

Hey I need some help and I know RM is not the only game in town but would love for my engine to be stamped with their name. I need some guidance I am doing a LS build for 1980 Corvette and am forced to go LS because of hood clearance. I want to do a Procharger probably F1X or something that flows a lot of air at lower levels.My goal is 1100-1200 crank HP. I want it done right but need to save wherever I can. I need around a 9 1/2 to 1 and around 600 HP base HP. I am thinking LSX 376 but really want 427 to have a little more ump before the Procharger. I saw where Texas Speed sells a LSX 427. I will have a pretty good size boosted cam amd may even drive it awhile before the Procharger is added. And heads either the chevy ones that come and get them ported by Yelvie or RM or just buy some ones aftermarket heads. I like that LSX 376 and it has a warranty up to 15 psi but it would cost to much to make it a 427. If anyone has some idea's would appreciate it.. I am thinking maybe I should start with an Iron block to stay safe. although an aluminum sounds really good. Thanks DD

 

And Reher Morrison has bigger fish to fry than LS engines. They will do them but is not their every day job.

 

Danny, that sounds like an interesting build for your 1980 Vette. It should be pretty easy to get the car close to 3,000 pounds or less. With a full tank of gas and a heavy iron block Dart SHP, mine is at 3180. A thousand wheel hp in a three thousand pound or less C3 would be pretty insane

C3's can be a lot of fun when sorted out. I have a few questions.

Auto or manual transmission?

What cooling she upgrades are planned? My 72 Vette has a DeWitt 's with dual Spall fans for my Dart 400 and typically stays in the 190-210 temp range.

It's my understanding stock cast iron rear end in my 72 vette C3 is maybe good to about 600 flywheel hp or about 500 wheel hp. With sticky tires maybe less. The aluminum housing 79+ rear is probably not any stronger. Tom's has some aftermarket rears that are capable of ~1000 hp. What rear end are you planning to use at 1000+ hp levels?

Likewise, the C3 frame is pretty flexible from the factory. I've been told stiffening by welding in reinforcements a good idea for any C3 that sees hard autocross or serious track duty with sticky tires.

I think a take out supercharged LSA or LS9 engine would be worth considering if it will fit under the hood line. The piston oil squirters give extra piston cooling which is always a plus with forced induction. I think LSA/LS9 would be easier to install than the ProCharger in a C3. The LSA /LS9 could probably do 800 whp but might take a lot of effort to get 1000+ whp. Like, different, pulley, cam, ported heads & ported blower snout. However, it's a 376 not a 427.

Using an LSA/LS9 with the 58x crank could probably allow using the eight speed automatic if the factory PCM and transmission computer are used. Probably take a custom wiring harness. Speartech excells at those set ups and would probably have good insight.

A take out 427 LS7 with a Procharger and cam swap would probably do pretty well too. The LS7 is more fragile than the LSA or LS9. Since LS7's can hit 650 whp NA, 1,000 whp with a Procharger probably wouldn't be much of an issue.

​​​​​​
Speaking of Reher-Morrison, Darin Morgan had a 5th Gen SS Camaro when I talked with him last year that's his daily driver. Darin is an engine master ​​​​​​that can make anything faster and better. I think his and RM's level of mastery covers all types of domestic engines.

 

thread is wide and awake again!

 

Hey thanks, Sounds like you have a kick-*** car. Mine is a work in progress. Yes it weighs 3200lb now. I was gonna go with a LSX-376 but I think I have decided to let Gary Ochs performance in Plano Tx do the engine with Fast LXR intake and install the Procharger F1. I would like to limit my shift at 7,000 rpm.

The car now has a rebuilt Turbo 350 and a stock rear end with 3;70 gears. Eventually 4L- 85 trans and new rear-end mini tubbed with the rear factory wheels sent off to ad 2 more inches towards the inside of car.

. It has a aluminum radiator. I decided to make the base engine have a little more ump so he wants to build a Dart 427 maybe 600 hp base with some sort of LS3 heads maybe Trick Flow 245 and cathedral. But I think I want rectangular heads. I think LS engine sound like a blender chopping ice so maybe rec heads will sound more like a small block.?? Anyone know about that issue?

He wants to build it 10.5-1 but I only want 10-1 or less so maybe it will be a pump gas instead of E85. I want everything to fit under hood and I want quieter good smooth sounding exhaust but need it to handle the 1200 or so crank HP. If it had 8-900 whp I would be ecstatic . That is what I think I need he thinks I need a little more. I haven't had a street car since the 80's. A 74 SD Trans am built by Nunzi of New York it ran 10's with a cheater system and was one of the fastest in the DFW back then. But boy how things have changed..

I have already purchased 3" Dynomax Ultra flows and also 18'" Race Bullets for resonators. The car should look factory except for a tach on the dash. I really would like to run less than 15 lb boost but will do what this guy says.

I appreciate any tips on it like how to shave weight off and if you prefer Cathedral or Rec Heads.

 

74 SD TA that's a sweet ride Sounds like a fantastic car back in the day!

I think there are two main reasons the LS engines sound like they do instead of like a traditional small block. The firing order is different. There are some issues for #7 with the traditional SBC firing order.




Typically, small block Chevy 's have an iron block & iron heads or iron block & aluminum heads, the LS engine from the factory for a Vette or Camaro or Firebird is an aluminum block & aluminum heads. To me iron block engines typically sound better. Even an LS Gen 3/Gen4 iron block sounds a little better than its aluminum cousin.

Cathedral vs Rectangular has the makings of Hatfield vs McCoy to the true believers

For big 427, that can move a lot of air even NA, I favor the big rectangular port heads. With forced induction either head can make a lot of power. For the 1,000+ hp ranges might as well go with the big rectangular.

My pet rule of thumb up to 400 cubes cathedrals are worth considering. 400+ to 420 pick your poison. 420+ rectangular.

I like rectangular for your big cube, big power forced induction build.