LT1 HEADS

[BOSSMAN]

Here are some LT1 heads I've been working on for awhile now, they are the #374 castings (thicker for porting). I'm currently roughing everything in as far as the port work goes. They are currently flowing 285 cfm @ .600 lift (28") with a 190cc port and 2.00/1.55 valve sizes. Thats about 70-75cfm gain over stock ports (170cc) that peak flow @ only .450 lift. These heads are competitive against some Lloyd Elliot stuff! Here are some pics of the progress so far.

Custom Valve Job:

Intake Port Comparison:

LT1 Chamber - Modified:

Ported Exhaust Port:

Ported Intake Bowl:

[BOSSMAN]

Finally got the valve train parts in for Wes. Decided to go with the Patriot Gold spring set up with titanium retainers. I'll try them out and see how they do (prefer to run the PSI LS1 spring). Also running some after market LT4 lightweight valves 2.00/1.55 and put some backcuts on them.


Also started hand blending some of the chambers and ports today. They still need the final polish on the chambers. Still playing with the ports to squeeze what I can out of them. These heads flow near identical to some AFR heads I did late last year.

[fivestarauto]

is there no room to up the exhaust valve size?? 1.55 looks so dinky isnt that stock valve size?

[BOSSMAN]

is there no room to up the exhaust valve size?? 1.55 looks so dinky isnt that stock valve size?

I believe the stock size is 1.500 and you can only go as large as the seat will allow which happens to be 1.550. The only other option would be to put larger seats in the heads to allow larger valves to be run. On LT1 heads with stock seats the biggest valves you can run are 2.00 / 1.550. I'm still looking for a junk head (not the #561 casting) to put larger seats in and play with valve sizes, port volumes, etc to find what is max for these heads. If any one has one hook it up!

[fivestarauto]

fuckin lt1's

[TireFryer]

Just out of curiosity...

What would it cost to have you do a set of heads like that?

I'm not as freaky about it as before, but my original project path dictated everything done under the hood use factory castings so it looked like a bolt on car. (I mean a vortech is bolt on, right!)

I can start digging around for heads

[BOSSMAN]

Wes has $1500 in these heads as of now. That is using his castings, cleaning, surfacing, Lightweight LT4 valves (aftermarket), Portwork, Flowbench time, Patriot Gold Spring Kit, and final assembly. These heads are pretty killer for the port volume and valve sizes. This is what I would call maxing out a stock casting. There are some things that could be done different to get them done cheaper. It all depends what you are trying to do with your motor. Feel free to give me a call if you are interested in getting a set done and we could go over it all.

[TireFryer]

Its something i'm interested in...
But I'm pretty much done spending money on this pile for the year.

Next year is up in the air, the other car wants some love.

[BOSSMAN]

I ended up having to weld the pushrod slot up to achieve a certain Cross-Sectional Area for this build. The port walls were getting too thin and since it will see nitrous I didn't want to take the risk. There wasn't any other way around it. I hope to gain a little more flow during the process.

The ports are all blended in just a few more odds and ends to go for the final flow figures and assembly.
Blended Bowl:

Blended Intake Port:

[atomicsix]

looks like alot of work, nice job!!

Unbelievable what those heads can be made to flow!!!

[BOSSMAN]

It's not an easy task but I wanted to show others what it takes to make them work. There are lots of details that I won't put out there since that is what I get paid for but these are killer. I flowed them again after the welding and picked up 3 more cfm @ .600 lift but they now pull all the way up to .750 lift and now flow 295cfm! This is a stock casting with a 2.00 intake valve and under 200cc port volume. - It was a pain to get the last 5 cfm out of them but hopefully worth it in the end. Hope Wes is happy with his heads!

[BOSSMAN]

These heads are now done!