KFC_Or_Bust

iTrader: (5)

Ok so I'm pretty much a noob when it comes to porting and milling, but I'm having a shop do the work, so bear with me please!

I have a 99 T/A, keeping the stock bottom end and slapping on 243s and a Fast 92. As far as the heads go, what can I get them milled to and still run 93 octane and not have any valve contact with the pistons? Keeping stock valves also, just a port/mill job is what I'm looking for.

My cam specs are .610/.614 242/246 110 lsa. Running Patriot golds and hardened 7.4" rods, would I have to go to a different set of rods if I get the heads milled? Also, what thickness head gasket??

Like I said, total noob, any help is GREATLY appreciated.

bwolfZ28

iTrader: (40)

You probably want to keep your DCR around 8.5-8.7 to 1 on 93 octance. And you should always check your swipe pattern to determine your pushrod length.

1999BlueTA

iTrader: (34)

That's a decent size cam huge in the eye's of many, imo you will have to flycut if you mill any, your close now with stock 243's so check your PVC!!!

Grr

iTrader: (2)

IMHO you cant mill ANY without cutting the pistons. So you may as well cut and take .030 off the heads and run it

Coach62

Just use a .040 head gasket and check PV clearance. The thinner gasket would effectively make your CC smaller by around 1.5cc. If you still have ample clearance, you could use the measurement figure to see how much you could mill the heads.

I know of people using static CR's of 11.5, with my new heads I plan on running around 11.4

dodson55

iTrader: (18)

with that cam ptv will be tight even without milling the heads i would cut the pistons and then mill your heads to get the compression ratio you are looking

KFC_Or_Bust

iTrader: (5)

The short block is staying in the car, just swapping my stock top end for better stuff, so I guess milling is out of the questions since it seems like I'd have to flycut the pistons with pretty much any mill work done.

PREDATOR-Z

IMO I would fly-cut anyways and mill heads since they are off. You'll will benefit from increased compression on such a cam.

jridenour31

You would have to mill quite a bit to have a dcr too high for pump gas with that cam. However, pistons will definitely need to be flycut.

KFC_Or_Bust

iTrader: (5)

The engine is staying in the car and in my garage so unless the pistons can get flycut while in the motor, they're staying stock lol. I'm not going for all out max hp for this build, I'm going 6.0/ls3 heads for when this motor takes a dump, I just want more power with parts I already have.

dgcustomz

iTrader: (127)

If this is the case then don't mill the heads, check ptv with stock head gaskets. If you have good clearance then see if you have enough room to run a thinner head gasket. IMO you will need to stick with stock gaskets and stock unmilled 243's.

KFC_Or_Bust

iTrader: (5)

That's fine, I knew it wasn't as easy as milling the 243s and slapping on a new gasket so I had to ask to make sure I didn't have catastrophic failure.

yomama

iTrader: (9)

Everyone is telling you need to flycut those pistons anyway. A cam that big will make kiss marks in the piston no matter what head you have. I hope you dont miss a shift cause then its all over ka boom. Flycut and mill to get the most out of the set up. But if you dont flycut you have been warned. Oh and some more food for thought im pretty sure ls6 valves are .050 taller so your preload on the rocker will be tight adding to your clearance problem. I would definitely check PTV clearance and buy an adjustable cam gear set so you can retard the cam if needed.

KFC_Or_Bust

iTrader: (5)

Well I've been running the cam on stock 853s with the Patriot Golds for a year and a half so there goes that theory.

batboy

iTrader: (6)

The 243 heads have 2cc smaller chambers than the 853 heads. This mean 243 heads will have tighter clearance.

Grr

iTrader: (2)

Negative, smaller chamber valves are in the same place

If you been running it, did you check PTV before? I bet its tight, but if you want to put the 243s on DO NOT mill them

Bbuchanan11

Im running milled 853s with a 231/235 .617/.621 112 LSA cam with thin fel pro head gaskets and I do not have fly cut pistons... but I dont have nearly the duration that you have

IllusionalTA

iTrader: (9)

Lot of experts in here... Check valve drop w/ a checker spring see how much clearance you got and go from there to determine whether you need to flycut or not.. This do i or don't i, don't work in the real world.. 20 min of checking can save ya 20hrs of labor..