Sorry to ask more LT4 hot cam questions but I tried a seach and went through many posts with my questions still unanswered. Most of what I saw was more modified engines with either MiniRam or something of that sort.
I was considering putting this cam in my 5.7 TPI but I wasnt sure exactly what is needed.

Would this even worthwhile swap with stock TPI and L98 heads.

I understand I need 1:6 rockers instead of the stock 1:5s. But is that just on the exhaust side or is it on both.

What springs would be recommended (part numbers or just specs) and what other modifications would be required to get the cam to operate at optimum performance.

Thanks
Eric

 

The LT4 Hot Cam will give some good performance gains with the stock TPI base. However it is far from ideal. You cannot use the L98 heads in stock trim tho.

As far as heads work goes...they need to be pulled and sent to a machine shop for work. I would have the spring pockets cut to 1.45" and throw all that 1.25" valvetrain in the trash. Put a set of Comp 986 1.45" springs on there. Also you will need to have the valve guides clearenced for the extra lift.

Since you're going through all that trouble.....might was well just throw a stealthram in the mix too????

 

Not true. You don't need 1.6 rockers to run any cam. They will just add to the duration and lift which, considering you're gonna run it on a stock tpi setup, you don't need nor want. Unless your planning to upgrade the rest of your combo (heads and intake) later, you should look for a smaller cam. Slow is correct, this cam in your application is far from ideal. You want your cams powerband to match that of the rest of your combo. The stock tpi engine doesn't do squat above 4,800 rpm and that were the lt4 hot cam will start to take off. So, combining an engine designed around low end torque, and a cam designed around mid to high end power will get you neither. I think a cam for you to look into is the zz4 cam. Still a good improvement over stock, but not to radical to be able to compliment your tpi. I am not sure if your stock valve springs can handle the lift though, thats something you need to take a long hard look at with any cam swap.

 

thanks guys I maybe planned on a mini ram later on but not right now so may just look into the zz4 and try something along that lines.......

speaking off what recomendations do people have for the zz4 cam swap? Im gonna also do a search and see what I can come up with.

Thanks
Eric

 

I have the zz4 in my car. It's a great cam for a stock tpi. I had stock tpi, stock heads, and the zz4 cam and it runs great. Has plenty of vaccum, and idles perfect right around 600 rpm. From what i've been told the tpi likes dual pattern cams and the stealth ram and similar intakes like single pattern. If you want lots of torque for right now, add the zz4, hog out your tpi setup and be ready to light your tires up.

But now i'm going to a stealth ram, fully ported aluminum vette heads and the lt4 hotcam since it'll all match up. If you're interested i'm selling my used zz4 cam. It's only been in the car for 9k miles. I can get pictures when I take it out tonight if you're interested.