So I have a stock 72 350 out of a Blazer sitting in my garage and also a 91 speed density TPI setup. I'm looking for a good daily driver with maybe 300 hp and hoping to find a cam that will help the TPI to keep pulling to maybe 5200 rpm or so if possible. Am also planning on converting the old smallblock to hydraulic rollers. Does anyone have any experience with any of these cams on a pretty much stock engine with iron heads? performance, streetability, gas mileage?

zz9 cam
LPE 219
XFI268HR-113

any help would be greatly appreciated. I posted this question in the TPI forum and got zero response.

 

Regardless of what cam you put in it, the stock TPI will drop off at about 4500 RPMs. The bigger the cam (as in more duration), the less usable powerband you'll have. You want to raise the powerband, you need to modify the TPI - shorter runners will get you to the 5000-5500 RPM range. A Holley Steath Ram won't cost you any more than modifying the TPI, and will raise the powerband to 6000 RPMs with a proper cam.

A '72 Blazer 350 will have crap heads. They'll be fine with a stock TPI and very mild cam, but you aren't looking at 300 HP. '87-'91 305 TPI heads would be much better, and would help raise compression if the 350 still has dished pistons in it.

Retrofit roller lifters will be pearls on a swine. Waste of money. Just get an appropriate flat-tappet cam.

 

So 305 heads would actually be better than breathing than my 350 heads. I didn't know they were that bad I was hoping 72 was early enough to still have decent breathing heads. Anyone have any other head suggestions preferrably under 800-900 bucks.

 

Vortec heads are very good, or aluminum fastburn vortecs

 

1970 was the last of the higher compression 350 heads. Trucks never got anything good, performance-wise.

If you go with Vortecs, add another $400 for the Vortec base. You'll still need runners. Or, the Stealth Ram comes in a Vortec version.

 

Can't you modify the base to fit the vortecs? I thought i seen somebody do that

 

Not really. Some 305 head castings are better or can be made better but many 305 heads are too small. Everyone seems to think using a 305 head with it's smaller combustion chamber is needed for more power but they usually fail to realize that the smaller valves and intake ports will really restrict the breathing to a bigger engine.

The TPI intake mount holes will need to be modified to mount onto the older heads.

 

You might have seen it, but since the ports are in a different location, it a stupid thing to do.

The 081 castings ('87-'92 305 TPI) have 1.84"/1.50" valves and 160cc intake ports (same as L98 heads). The '72 Blazer heads will have 76cc chambers and 1.72"/1.50" valves with something like 155cc intake ports. The f-body carb and TPI heads are without doubt superior to old truck heads.

 

i stand corrected then. then 305 heads are the bang for the buck here

 

Some people think all center-bolt valve cover heads are "Vortec" - that ain't true. The center-two intake mount bolts are at a different angle (on the factory iron center-bolt valve cover heads, that is), and for that you can modify the bolt holes on the intake to get the bolts in for an '86-earlier mount bolt angle intake.

But, with true "Vortec" heads, you only want an intake made for Vortec heads.