I have a 2000 5.3l engine with a set of 706 casting heads. whats the biggest cam i can put in it with out changing out pistons? I really like the ms4 239/242 .649"/.609" 111 lsa. Maybe a dumb question, but cant find much info on using stock 706 heads. I can get the cam pretty cheap now and plan on putting on some 317's later when my funds permit.

 

you cant use 317's on a 5.3 and that cam is too big.

 

You can use them... Its a great way to lower compression on the smaller engines. Good on FI, not on NA. You do run into valve shrouding issues though with the smaller bore.

But I would agree that the cam is too big. We need more details of his setup.

 

My brother has a Speed Inc. SI5 231/237 .589/.595 112 in a 5.3 with ported heads and 3500 stall in his 3600lb Chevelle. IMO, it's too big, he should have stayed below 230. It sucks having to spin a stock bottom end engine up to 7k rpm where peak power is at. Scares me every time i do it.

 

No point in running a donkey dick cam if the heads can't match what it can flow, it will be a dog. Plus you will need a 3600+ verter... Pointless imo unless its a full on race truck...

 

Ok. The engine is in a 79 camaro. At the moment, it has ported 706 casting heads and full bolt ons. I'm running the 1.85 ratio roller rockers from comp cams and yellow ls6 springs and didnt notice much difference in performance. The car is by no means a daily driver. Oh and after a little more research, i will prolly go with a set of 241, 853 or 243 heads. My buddy has a 01 ta with a ms4 and i fell in love with the choppy idle and performance.

 

Oh and before ya'll say it, I know I will have to go with some double springs and go back with the stock ratio rockers. I just wanted to know if it was possible to run the ms4 on a stock set up without hitting the pistons.

 

Do you really want an MS4 in a 5.3? Your buddies car is a 5.7 with higher compression than a 5.3 and that is a big difference when choosing a cam of that size.