Cast iron 624 heads (stock @ the85 vette)

[jan-erik]

Hi.
I have an 85 4+3, Z-51.
I try for fun to get the most out of the stock cast iron heads. I have asked some places about flow data of the heads, but have not found any.
The heads are now portmatched to a ported intake and plenum

I also wonder how much I can estimate to take out of them (torqe and hp)?

For stock looks I have the large tube runners

I have the TPIS coated long tube headers and good low resistance exhaust
I have the engine a bit overcamed: Hydr. flattapped, int/exh @.05 221/230, 112 lobesep and lift .454.

The chip is modified to the mods.
The engine pulls much harder than the stock did, but I have no idea how much I can await from it. Have I reached the max out of these heads???
Has anybody tried to reach the max out of these haeds even though they say that these are more valuable as anchors.

Would appreciate some comments on this

 

[Rogier]

Another european trying to make his vette perform better.

To be honest I don't know what you can expect from these last mods you are planning. What is the current output? Where did you get the long tube headers? For all I know the long tube headers do the major job on a L98.

Best regards,

 

[vader86]

yes, trash em

 

[grumpyvette]

jan-eric

the stock 1985 iron corvette heads can be ported to flow (BETTER).....but SKILLED PORT WORK GETS EXPENSIVE, AND they will NEVER come close to the flow of the better aftermarket heads flow numbers.
these are the flow numbers of the "BETTER" aluminum versions (below)
These make a good choice for a basic street motor looking to add a little more power over those of the gm cast iron heads, these are the corvette style heads.

• PORT SIZE: 163
• CHAMBER: 58cc
• VALVE SIZE: 1.94 / 1.5
• PRICE: N/A
• FLOW@.100: 56 / 49
• FLOW@.200: 120 / 96
• FLOW@.300: 160 / 123
• FLOW@.400: 186 / 140
• FLOW@.500: 196 / 155
• FLOW@.600: 199 / 159

as you can see there not that impressive

these are the flow numbers from a decent replacement head

http://www.airflowresearch.com/
AFR 180cc SBC Eliminator Street Cylinder Head

http://chevyhiperformance.com/techarticles/p104737_image_large.jpg

the DIFFERANCE in flow rates can easily mean a 45-60 hp PLUS advantage in power. especially if a cam designed for the TPI intake is used to boost the flow potential and take advantage of that increased head flow
swapping cams to something like this

http://www.cranecams.com/?show=browseParts&action=partSpec&partNumber=114132&lvl=2&prt=5
and those AFR 180cc heads will make a VERY NOTICABLE IMPROVEMENT, ESPECIALLY IF the STRONGLY suggested 3.73 rear gear ratio and fuel pressure regulator is also installed

since your already slightly over cammed the heads and swap to a 3.73:1 rear gear ratio,will make a your current combo MUCH BETTER and more effective