I'm trying to research and find out if the parts I have will make a decent combo before I assemble them. I have a Bolt On LS1 with 853? heads and I have Ported 241s and MS3 cam ready to install. Before getting to far ahead, will I have proper PTV clearance with stock head gaskets? Should I use the common 7.4" pushrod length? I'm unsure if the heads have been milled. Where can I find the deck height so I can check them? Just looking for some info before I have some piston/valve events..... Thanks

 

So I just read that the 241 and 853 heads are the same except the cast type which is not really important other than the fact that the 241s are ported and will raise the CR from 10.0 to 10.4. Are they even worth the swap? or should I just put the springs on the 853s and do the cam swap with the heads on.???

 

So the 241's have been worked over but the 853 heads on your car have not. Am I getting that right?

 

Yes But after talking to a friend, it sounds like its not even worth the change. The heads arent I mean. The cam is pretty large for a daily driven auto runniong a 3500 stall. He's even got me second guessing the heads/cam swap all together and going with a better stall an nitrous instead....

 

Well if you do that cam that would be the perfect time to go with the ported heads. Combined it's going to give you a noticeable bump in power compared to the stock heads

 

Which was the plan from the beginning. He explained the work wouldn't be worth the reward in his opinion as I could just install a 150 shot and run just as fast or faster. But I really want it cammed. I guess it builds down to owner wants in the end. As long as I'm not going back wards ima do it.

 

Well if it were me I'd at least cam it then hit it with some nitrous. That's just imo...

 

Cam it. If you do, you have the power all the time. Nitrous is only when you spray, which probably wont be that often unless your at the track alot.

 

I run the MS3 right now, and will be putting the AI HCR 219cc heads on it here soon. With that cam, the heads at 61cc and 0.40 head gaskets will put me right at an 11.1 compression ratio. Depending on how worked I we your heads are; you could be in that ballpark somewhere.

 

I ran the ms3 with unported 241's. With a good tune the car drove well, but without a decent set of heads it didn't really pick up much power. Why not sell both sets of heads and pick up some 799/243 heads to use with your cam?

 

I could do that but that will put the car down for a while. It is "spare" but I don't want it down for too long. Hoping a weekend swap and keep riding.

I don't race track enough to really consider nitrous a real benefit. I do drive it daily and want a fun daily capable driver with weekend track capabilities. So now I'm thinking I should prolly cam it, use the 853s that are on it and sell the 241s towards something else or save until I can get some better heads. I think that's the deal. I have everything needed to assemble the heads, dual springs, new chromemoly push rods, retainers, locks, new seals...I guess I will just be doing that IN THE CAR...Man that sounds like a job.

 

If it makes any consolation; the MS3 runs like a monster on nitrous.

 

Funny you say that cause my cam is almost exactly identical to the MS3 and I gained 120 rwhp off just a 100 shot. Maybe your are right

 

I'm running ported 241's with a slighty larger Comp Cam, My combo made 421hp at the wheels. LS6 intake, headers, and ported TB. Mock everything up and check PTV clearance with some puddy and you'll know for sure. Doesn't take that long to do it right.

 

Yeah but how many guys have ran this cam in a stock ls1. Thats the info Im looking for for PTV clearance. Maybe Ill just call Texas Speed.

EDIT: Found my answer via Search. Will clear fine. No need to check PTV with clay

 

Remember just because a cam clears when you turn it over, doesn't mean it will clear under load. Always measure. There needs to be a "safe" clearance

 

Double post

 

The whole idea of the magic stick cams is to be a max effort camshaft for stock bottom end engines. They're designed to clear the stock heads.

 

thats what im reading

 

If you mill the heads or put larger valves in as part of the porting/valve job process, you will run into clearance issues.

I like the idea of AI HCR 241s... they weld the chambers and keep the stock valves to bump the compression without affecting clearance. And the MS3 really needs compression - a lot of compression. Like 11.8:1 to run optimally. So 58.5cc chambers and a .040" gasket paired with an MS3 would be beastly with AI's port program.