I think I’m problem wrong on piston cc dish,just doesn’t sound right with flat tops in a 5.7.ill see if I can google the piston part number and get an exact cc on them.. some of the 383 kits are says there flat tops are a 20cc dish.. I have a 377 with 64cc dart heads and that is 11 to 1.made 450 on the Duno,my machinist said if I swap to big chevy bowtie vortex heads he sees it going another 70hp.. so with that in mind I want to make shur I get best flowing heads I can out of the gate,weather it’s ported stock or after markets.

Without knowing your budget, it's hard to help you. Worked stock LT1’s with matched cam are under $2,000. The maxed out Trick Flows, w/ 0.700” solid roller springs are over $3,200 plus $400 for the cam.

If you are interested in the 215cc Trick Flow heads, click on the link above for their worked TF’s, good for 600+ HP. They also offer the TF 21° heads.

Hopefully that Eagle crank is forged, not cast.

Ok,so here’s what I have already...... long tube headers,bbk 52mm throttle body,eagle 383 rotating assembly, flat top wisco 2 relief piston on rods.... I guess the question is,is will the car make more power with like a trick flow or an afr head vs have a stock set ported and intake.. is it worth spend an extra grand on aftermarket heads that’ll flow another 15 to 20 cc...I’m really new to the lt1 first on I have worked on so I’m trying to find out what my best options are to make most power and run pump gas...

I mention what I do have just because I bought it all for less then 400 and crank n rods are nice,so I saved a lot of money ther so I can afford to spend some cash on top end.the le3 heads form Elliot flow 195 200 and the price with cam is great cus they spring heads also.

Why are you focusing on the exhaust flow on the LE3 heads? And “heads that flow another 15 to 20 cc” must be a typo. cc refers to the volume of the intake runner. Flow is CFM.

Both those links I gave you have estimated HP capabilities. AI claims up to 530 rwHP for their 200cc ported stock LT1 heads. That ~600 HP at the flywheel. The car is running 9’s @ 138 MPH, ON PUMP GAS. The LE3’s are about 500 HP at the flywheel. But at that point the question becomes can you live with the reduced drivability on the street. Big cams make big power..... at the top end.

You indicated your goal was 500 HP at the flywheel. Then you mentioned a small shot of nitrous. Stock heads can meet that. And I'm sure you're aware that the rest of the driveline is going to need an infusion of $$$$ at those HP levels, as will the suspension required to put that power to the pavement.

The stock flat top pistons have 4 valve reliefs, totaling 6cc. 20cc would indicate a true dish, not a flat top.

It was a typo,my spelling and grammar is horrible lol.. thanks for the input guys. I got engine out today guna get it to machine shop.ill keep ya posted in shur I’m guna need more help as project progresses.