Pro Topline 200cc 72cc straight plugs or Pro Topline 220cc 72cc straight plugs for my 5-Speed TPI 383? They are the same cost and Flow rates are almost the same. A little better for the 220cc. So I am guessing the 220cc should work better.

Also I am running Hypertech pistons #H600CP .030. What would my compression be on them and with those heads?

Thanx

 

A 220 cc port will probabily make less streetable power than the smaller 200cc port. Certainly less torque. Port velocity would be sluggish at low and mid rpm. The GM TPI Induction is not a high rpm intake. The runner length is too long and too small for high rpm. Pure physics. I'd even consider a smaller 170/190cc port for this. Best to combine a head with the same port cross sectional area as the intake manifold ports.

On a 383 the 220 cc port head would be better matched to a higher rpm intake like the short runner Mini-Ram. and a larger cam.

Again, of the two choices I'd pick the 200cc port. A little port cleanup work will more than make up the difference inflow.

You can calculate the actual compression ratio your self,
at this link below. You'll need to input the piston dome/ relief volume and piston to deck clearance.
Every motor varies some so you'll need to measure this clearance your self.

Compression Ratio Calc




HardCore HotRods

 

Thanx

I am going to pro-charge it in 2 years. Thats Y I also hoped to find out my compression. So with supercharging would the 200cc still be better??

 

I'd go with a better intake to start with. The TPI intake is pretty but really limits the RPM ( topend horsepower potential) of your motor.
A SuperRam, Stealth Ram. Mini-Ram or other short(er), larger runner hi-perf EFI manifold will work better. Especially with a blower(later).

Design and build the motor right and you can probabily skip the blower.

At any rate the large port 220cc head is a mismatch on a TPI motor.


HardCore HotRods

 

Not to hijack this, but I am ordering a set of these soon and am curious what size to get?

I was going to get the 180cc since they will be on a fairly tame 350 that shouldn't see over 6,000 rpm. Is that right or do I need the 200cc heads?

 

Taking a wild stab at it. If the 220cc are to big for my 383 and I should go 200cc then I would guess that the 180cc would work great for your 350 set up.