LT heads do NOT impress me.....horribly inefficient

With that intake port size and location (the floor of the port raised 1.5" or so above the head deck) they should easily flow 50+ CFM more even as cast

They are close to 300 cc's stock and only flow around 305 CFM. The floor of the intake is at least 3/8 of an inch higher than even an LS7 head and its only flowing 305 CFM with a huge port!??

That's honestly kind of pathetic. Are they better ported.....sure but not by a huge margin.....340 - 350 CFM and now the port is even larger

A factory LS7 head is 270 cc's and flows 365 CFM right out of the box (with technically a lower intake port which is a disadvantage from a design perspective). My aftermarket 265 LS7 heads are 404 - 414 CFM depending on valve and porting options as another reference point.

In short the LS7 head crushes an LT1 Gen V head....its embarrassing its so bad. Hell my aftermarket 12 degree LS3 heads flows 385 - 390 CFM and that head is only 260 cc's.

The ONE thing they did to improve things in an LT Gen V deal is the move to direct injection.....that's worth gains in efficiency (fuel economy) and torque output but you wouldn't be running that in your LS deal either.

I could SHRINK the LT intake port with about 40 cc's of epoxy and pick it up 40 CFM in the process making it a bunch more efficient (and much higher airspeed). They really dropped the ball on the short turn of the intake laying it down and negating all of the gains that could have been had with such a tall ideal intake port location.

And the hooked exhaust port.....another mess to further reduce the effectiveness of the exhaust port and the cylinder heads potential output.


Honesty I have stayed away from messing with them for the most part because I was convinced that GM would have made a radical change in the port configuration/shape by now as the term low hanging fruit doesnt even begin to cut it. This port design is so easily improved on but it would require ADDING material in the right places to improve its flow characteristics (and subsequently a big gain in airspeed which is every bit as important as air volume).

So yeah.....no love for the LT Gen V heads here at Mamo Motorsports.....LOL

Naturally I have helped some folks with ported OEM LT castings and make them flow and perform better but I don't go out of my way looking for that business because at the end of the day its just not a product I can get real excited about

That doesnt mean that ported LT1 casting with 340 - 350 CFM's with direct injection cant make power.....

Its just that as a head designer by trade, I look at the location of the port, the size of the port, the size of the valve (and the valve angle) and I know I could have gotten sooo much more from that architecture....to me its a huge GM disappointment.

Consider these stock flow and port volume numbers and history of the LS / LT platform

1st Gen LS1 heads........................205 cc / 230 CFM
2nd Gen LS1 heads (243)..............211 cc / 255 CFM (nice gain with minimal volume increase is a winner)
Rect port LS3 heads..................... 260 cc / 315 CFM (Big gain in flow and a big gain in volume....so so in efficiency/airspeed)
Rect port LS7 heads..................... 270 cc / 365 CFM (the pinnacle of OEM cylinder head architecture IMO.....10 more cc's over an LS3 but 50 more CFM!!)
LT Gen V heads............................290 cc / 305 CFM
Mamo 265 LS7 heads...................265 cc / 414 CFM Shameless plug only to show what a well designed smaller port is capable of (BIG airflow and BIG airspeed....that's the hot ticket to insane performance and its not easy to achieve)

With so much going for it in terms of the architecture/port location, LT heads flow worse than a decade older LS3 design with a taller port and a larger runner and a flatter valve angle! Poor design....very inefficient

You want your LS engine to make a bunch of power and accelerate hard....steer clear of an LT head and put a properly sized efficient aftermarket LS casting on it.....I may know a guy that can help

Hope this post was helpful

Catch you guys later

-Tony