Hey guys Im new here in this forum well i got a 99 Z71 5.3l and upon changing headers(Pacesetter headers) on my truck found that the stock heads had header bolts broken off inside. instead of paying someone to do the work I would like to install new heads. I was thinking of stock LS-6 heads and need help on determining cam size, springs would be the 918 springs. Can anyone help. This truck will be a daily driver I just want more power inside.

 

if i may say one thing in my experience with 918 springs. i have found them to break more than anything even with mild .221 dur .558 lift 114 lsa cams. i recommend looking into the patriot gold double conical springs just as a precaution. and they cost about the same.

as far as a good cam for the 5.3L i cant help you too much. im also looking for answers on this. i do know thato n a 5.7L ls1 engine with no headers and only mods being the cam i listed above, with an intake and a catback the car made 385 rwhp on a dynojet.

 

yeah thats the kind of horsepower i am looking for. Patriot has a good deal on their LS6 heads milled back down to 61 instead of 64 otherwise i wiould lose compression. I will check into those springs. But my friend has LS1 and has extra 918 springs and he highley reccomended those.

 

its up to you whether or not you would like to use those springs. no doubt theyt have worked for some people. however i have personally seen a minimum of ten cars break them. but i guess thats also in a manner of how you abuse your vehicle. these cars were track goer's at least once a month.

dont expect to make that much HP from a 5.3L from what i have just researched with a full range of bolt ons youd be looking in the neighborhood of 330 rwhp on a dynojet and about 290ish maybe more on a mustang dyno (loaded).

 

Good luck making 385 on a 5.3L. There was just another thread about this yesterday.

Check for update's on Closet Redneck's dyno numbers he just threw in a 224/228 110 lsa cam with dart heads milled to 11:1 compression. He's hoping for high 300's power and he has every single bolt on/cam/heads/etc

The 918 springs are what most people run. He's right about them being brittle though. You have to baby the truck until it gets to operating temperature so the springs can get some heat on them.

For a cam it really will depend on what heads you want to run but I would say something like a 224 or 226 split duration cam on a 112lsa. That's just me though.

 

thanks for the help guys I will look into all this, I dont expect high 300's but just to break into 300 hp would be nice. its a 4x4 so i want be runnin down the track much and since I am not back in texas it wont see much off road action either.

 

Howdy- still kinda new here. If I may ask, what's the profile of the stock cam?