well the 853 is not a great head but it is the 99-00 LS1 head after that they went to 241's
the truck 243's are a better casting but have smaller vavles I think (ls1 are 2.00/1.55) so if you were to port them I would say the 243's

if you are going to stroke it you might consider what I did is a 396ci
383 is a 4.000 stroke on a 3.905
396 is a 4.125 srtoke on a 3.905
on my old car we made a good amount of power but the torque curve was strait across

 

Any longevity issues with such a long stroke? Piston leverage issues, Liner wear? that type of thing.. This is going to be my daily driver.. I really only want to have to have this thing down once.. That would be cool... To say you have a 396 in your truck.. LOL

Anyone near INDY that can suggest a good machine shop to take this thing to?? That can do head porting?

Thanks for the feedback keep it coming..

 

well what I did is I went with a 4.125 stroke crank, 6.250 rods, and custom pistons now the pistons had a compression height of .97xx I cant remember the exact number but is was just under 1 inch, now this is because of the 6.250 rod instead of a 6.125 that 1/8 inch had to be made up some where with a 9.240 deck height (I think thats it)
now my friend Reza (Trust on tech) did a 396 also but with a 6.125 rod and custom pistons with a D-1 at about 18psi and making 800rwhp and no problems there either

The only think I would do is make sure to grind the cam with added cam timing that will bring your peak power down in the RPM this will also help move the torque into a more usable range as well IMO. this is all because you're right I wouldnt want to spin a motor with such a long stroke to 7000rpm, sure it might be fine but still.....

also think about selling the LS1 and getting a 6.0L iron block and building a buget minded 408ci?

 

I would like to build a 6.0 or just buy a 6.2 and swap it in.. But the LS was free.. And i cannot sell it.. I am going to use the LS block and build a streetable hotrod engine.. That is my goal.. And GOBS of torque..

I may try to work a deal out to get a 6.2 in trade for the LS1.. Anyone interested in a trade can PM me.. LS1 is very low miles.. Exact number is unknown..

 

Well, the ls6 made 405 horsepower with 243 heads (take em off your 4.8) and 346 inches. So on a 383 with a real cam, headers, and maybe more compression.. **** oughta fly

 

GOOD feedback. Didnt realize that the LS6 had these heads.. Yeah if that is the case this thing should be sick.. Great.. Good news.. Thanks, you personally brightened my day..