That EFI is choking your the flow capabilities of of your ported heads.
I ran a Holley 950 cfm carb on my 512 and I believe it would have taken more and that was with a set of old school ported iron heads.
How about your intake was it port matched to your TF heads?
I believe they are machined to match. Flow may be an issue but the Super Sniper is rated to 700 hp aspirated and 1250 hp boosted. So I thought it was enough
