TxFireman1972

iTrader: (8)

Putting together a 5.3L for my 89 Mustang Coupe. After seeing a couple of other guys having success with the Texas Speed MS3 (237/242 .603"/.609"), I'm going to give it a try. I picked up a set of 243's to put on the motor.

I've read till my eyes crossed and haven't found a solid answer. My questions is how much can I mill the 243's if I'm running the MS3 on my stock LM7? I know the PTV will need to be checked when it goes together, but trying to see if there is anyone running this combo, or someone that give me more info. Thanks!!

badazz81z28

iTrader: (6)

I would say None. Unless you don't have any problems flycutting the pistons.

TxFireman1972

iTrader: (8)

I dont mind fly cutting if I have to. Anyone else?

badazz81z28

iTrader: (6)

Are the pistons dished or flat tops?

If you don't mind cutting....slap that cam in, measure and cut away. You MAY even have to flycut with no milling as well.

FYI...Nobody here can tell you for sure if it will clear on your set-up

TxFireman1972

iTrader: (8)

5.3 with the dish. Like I said, I know I will have to check, but trying to seeing if anyone has run a similar combo, and if so, how much they milled. Thanks.

EricYJ-TA

iTrader: (10)

Im running a MS3 with 243 heads on my 370. Milled them .10 and everything clears just fine. But i am running pistons with -4cc valve reliefs.

TxFireman1972

iTrader: (8)

Is there a better choice for cylinder heads for the 5.3? I would love to have a set of the Texas Speed 2.5 heads but just not in the budget this go around. The motor came with 706's on it. I got a good deal on the 243's so I picked them up. So looking at it I guess my options would be:

A) Mill the 243's and flycut the pistons to work with the MS3

B) Mill the 243's and find a different cam that will work without flycutting the pistons

C) Different heads

D) Unmilled 243's (which I believe would hurt me because of compression loss)

Like I said, several simple 5.3's on here running really good, so I'm following a lot of their setups. Just haven't really seen any of them running 243's. Any ideas, thoughts, suggestions, or comments would be great. I'm still learning as I go. So let me know my best route on a 5.3, with carb, Vic Jr, and some spray.

Ronny_02_WS6

iTrader: (6)

I would say:

B) Mill the 243's and find a different cam that will work without flycutting the pistons.

Thre are plenty of Smaller cams out there that perform great with the higher compression.

JustAFooL

iTrader: (45)

I have stage 2 Patriots milled to 59 with a Comp 224/230 and couldn't be happier. Clearance was .070 on intake and .1+ on exhaust. Just finished this setup and I'm EXTREMELY pleased. The added compression is where It's at to me. The MS3 is a great cam though, if you don't care to cut, I'd mill them down some and cut away. If you don't want to cut, there are plenty of smaller cams that will perform great as well.

AR's LSnotch

Am doing the same set up in my 93 coupe dropping a 2007 5.3L it has flat top pistons an I'm planing on runing the ms3 an using 243s but not doing work to them runing them as is would I have to check clearance or would I be fine. couple of my buddy's are telling me I should be fine I can even run a ms4 but the sayng is is to big but is it to big cus of the cubic inches on motor

PREDATOR-Z

Is your coupe a pure race can?

AR's LSnotch

Car gonna be a weekend car an see a lil of track

PREDATOR-Z

Too big of a cam for motor size.

AR's LSnotch

The ms3 to big ? Am new to this LS world so wat cam would u recommend me to run car gonna be N/A am looking for something that would work great wit the 243s an make great power wit ls6 intake looking for that choppy sound to