ok ive read alot about these heads but still come up with some questions. what roughly would the compression be on a 355 with these heads and flat tops? say i wanted to have them ported how well will these flow compaired to aftermarket iron heads? and how well would do they do with say fuel injection or a lt1 intake swap. i just found out that these are my castings and im wondering what there potential is. they are machined already for 2.02 1.60 valves screw in studs but i dont think they are ported.

thanks

im trying to make a new better matched combo with injection and a new cam and i want to get around 400hp if possible.

 

Compression would be somewhere in the range of 10:1, depending upon piston valve relief volume, head gasket volume, deck clearance, and actual combustion chamber volume.

Without porting, the only advantage over say L98 heads would be the higher compression. With porting, they will flow about as well as most iron replacement heads, probably close to or better than off-the-shelf Vortecs.

With 2.02/1.60's, you'll probably have to do some chamber unshrouding if it hasn't been done already, which will increase chamber volume and reduce compression.

 

ok i see. so pretty much im lacking alot of power from the combo in my sig because these heads arent ported or flowing near there capacity. how much of a gain could i expect if i have them fully ported. also should i have them polished ive heard that somtimes polished isnt always better.
thanks

 

The gain would be hard to guess. Probably substantial, but that old-school cam is probably holding the engine back as well.

Polishing is probably marginally beneficial as far as power is concerned. The theory is the polishing keeps combustion by-products from sticking to the chambers and exhaust ports. The primary benefit is probably reduced pinging by removal of potential hot-spots on casting flash peaks and the like in the chamber, allowing you to run proper ignition advance. You don't want a mirror finish on the intake ports, though, to help avoid fuel separation on the walls.

 

It's not cost effective to pay someone else to fully port these heads. You will have more wrapped up in them then the cost of new aftermarket castings. It just takes way too long.

Either port them yourself or get new heads.

i have never ported the 601 castings but have done lots of 416 castings. They are simular but not exactly the same. I get them in the mid/high 230cfm range. 170 to 190 exhaust. thats with maxporting.
Got one set to flow 242cfm.
I don't use or recommend 2.02's in these heads.
I use 1.94's and 1.60's.
It's not hard to do, just time consuming.
The edelbrock torker cam is all wrong for EFI.

 

they already have them in them. i bought them for like 500 bucks or so off ebay like two years ago. when i built the motor i knew how to put one together like a pro micrometer feeler/plasti gauges.now im gonna go fuel injection but am matching it better.

the old school edelcrap cam is as good as gone.. im getting a new one to match my lt1 intake swap. however comp cams tech guys dont have any suggestions for me because they arent farmiliar with the lt1 gen1 swap deal.however ive been reading up on them.



well i guess im gonna learn my first course in head porting.just found the topic on head porting looks fun and time consuming. anything i should know? looks like i need to take alot of metal off.
thanks for the help too

 

Yeah, follow the link at the end of my sig for the lowdown

 

Do you want a hydraulic flat tappet cam or a Hyd roller
for your LT-1 intake swap?

 

i want to use a hydraulic cam like i have now beause i dont want to put all the money into the roller swap i would rather spend that money on the intake.how much does it cost to go roller anyway?