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Does anyone know which small bore LS7 heads would work best on my bore size 4.030?
Seems with the responses I am reading on this thread this seems the right path to pursue.
If anyone disagrees say so and why.
Not that these are necessarily the best, but will give you a good idea what small bore ls7 heads can do.
Mast has them, but no pics or info, which likely means Darin is working on them. In which case, I would suggest staying up late to call and talk to Darin at Mast to see what he can do.
Not that these are necessarily the best, but will give you a good idea what small bore ls7 heads can do.
Mast has them, but no pics or info, which likely means Darin is working on them. In which case, I would suggest staying up late to call and talk to Darin at Mast to see what he can do.
Very similar results to my previous combo but with an extra 30rwhp.
What intake was in that motor?
Higgins Race heads have Darin's small bore LS7 heads down here.
He designed them and did the port program.
According to the op it was a ported ls7 intake. Sorta what Smokey is saying. By the time you spend $4k on heads and intake you will gain 20-30 hp. 100 shot be cheaper
that thread with the RPM heads is a mimic of what Darin done for me* they just don't show above .700 I do > exact to the number....Darin may have made that port for those guys...using the same casting. Who knows but a Stolen idea none the Less....been there did that.
ER was down with me on the idea...and also previously had done it.
I am running AFR 245 Cathedral heads, I have Kinsler ITB's so Im not going to junk those! My engine has a peak of 627bhp (crank) @ 7015rpm, and was still making 610@7500rpm, so holds on well, I only have inch and three quarter headers but its tight with those, and that i think is the bottle neck if anything. I am in the UK so our dyno figures are very different to you guys, but a 454LSX with a FAST makes 550 at the crank on the same dyno. Mine is a 419CI. You can see the extra cubes on the bigger motor down below then my engine keeps going.
Thats right, just cant remember everything. Im 31 now so i cant remember what I ate yesterday
Originally Posted by Darth_V8r
You and I went through this in a different thread. Top ten NA fast cars were ls7 or cathedral with one ls3 head in at 9. Three of the top 4 were ls7 iirc.
So, I just checked the top ten fastest NA LS cars list. Here it is:
C5R is the LS7 precursor, so I count it as LS7. MOZEZ is LS7. Edelbrock canted is LS7 - that's the "big johnson" heads. So if you wanna go fast, looks like LS7 heads and solid rollers is the ticket.
So, in the top 25 fastest NA LS cars list, you have one LS3 head, and it's 19th. Five cathedrals, with the best at 10th. Rest are LS7. Now these are all big inch builds, so you'd be leaning to LS7 heads anyway on those builds, but there you go. Fastest "small" bore is that 403 at 25th place running ETP 225 heads
Damn good list Darth.
Those LS3 heads are monsters regardless.
Getting into the 8s is still nuts.
My take on this is that the LS3 heads really shine on big engines.
My take on it is that once you get the engine big enough to really take advantage of the ls3 heads, you may as well jump to ls7 heads and take advantage of those at 30+ cfm better flow out of the same port volume, and better valve angles, and raised runners, and bigger valves.
My take on it is that once you get the engine big enough to really take advantage of the ls3 heads, you may as well jump to ls7 heads and take advantage of those at 30+ cfm better flow out of the same port volume, and better valve angles, and raised runners, and bigger valves.
What size engine do these LS3 heads really shine?
Cubes are more important than bore size?
Read an article that an engine over 400cid is where these heads work best but nothing mentioned about bore size that I could find.
What size engine do these LS3 heads really shine?
Cubes are more important than bore size?
Read an article that an engine over 400cid is where these heads work best but nothing mentioned about bore size that I could find.
Right, but you can make some educated guesses.
427 is most likely a 4.125 bore and 4" stroke.
454 is most likely 4.185 x 4.125
416 is usually a LS3 stroked stock bore, so 4.065 x 4
421 is usually a LS3 bored 030 over and stroked to 4", so 4.095 x 4
447 is usually a LS7 bored 030 over and stroked to 4.125, so 4.155 x 4.125
By the time you get tot he point you can fit the ls7 heads, you're better off doing so. Where I have seen the LS3 heads shine honestly has been on the stock LS3 and RPM. Another example would be a all bore 388. Spin to 8500 rpm. That's when I typically see the LS3 heads do their best. Aftermarket may be a different story. But most people will jump to LS7 style heads if they can fit them. For the reasons I mentioned above. Those are a lot of handicaps to overcome. Especially the short side radius on the cathedral and LS3 castings. Raised runners do amazing things for air speed.
427 is most likely a 4.125 bore and 4" stroke.
454 is most likely 4.185 x 4.125
416 is usually a LS3 stroked stock bore, so 4.065 x 4
421 is usually a LS3 bored 030 over and stroked to 4", so 4.095 x 4
447 is usually a LS7 bored 030 over and stroked to 4.125, so 4.155 x 4.125
By the time you get tot he point you can fit the ls7 heads, you're better off doing so. Where I have seen the LS3 heads shine honestly has been on the stock LS3 and RPM. Another example would be a all bore 388. Spin to 8500 rpm. That's when I typically see the LS3 heads do their best. Aftermarket may be a different story. But most people will jump to LS7 style heads if they can fit them. For the reasons I mentioned above. Those are a lot of handicaps to overcome. Especially the short side radius on the cathedral and LS3 castings. Raised runners do amazing things for air speed.
What is the minimum bore size your Mamo LS7 heads need to fit?
What is the minimum bore size your Mamo LS7 heads need to fit?
Don't know, I would need to ask Tony. He would likely say 4.125, but I would bet with a 2.20 vs 2.23 valve and offset dowel pins, it could fit an LS3 bore.
Edit - likely he would try to convince you to run his 260 ls3 heads instead, but that's a guess.
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