Which Collector Size on 408

[aengineguy]

Please give me your opinion on what size of collector to use on my combo, 3" or 3 1/2" as TTI has both available? I am leaning towards the 3" as this will be mainly street. Thanks...!!

1971 Dart Swinger
91 LA block .030 over, zero deck, line bored, Hughes Main girdle
Quite a few oil system mods
Standard Melling pump, not HV
Kevco pan and pickup with larger tube
Scat forged crank
Scat H beams
Icon forged pistons
Edelbrock Magnum Heads fully CNC ported by Hughes, 2.08" intakes, milled back to 58cc chambers. Around 300 cfm @ .600 lift
about 10.65 comp
1.6 good rockers
ARP head and main studs
Hughes Solid Flat I .610, E .614, I 252, E 256 both @ .050, 106 LSA
Solid lifters with EDM holes
Air gap with 750 HP holley (may fully port the Gap or go with an M1 single later, 950 Holley maybe later)
TTI 1 7/8 Headers
TTI 3" exhaust to the bumper
SFI Damper and Flex
Mallory #42 dist. with Hyfire 6 box and rev. limiter
Edelbrock 160 GPH pump pulling thru (2) Fram filters
-8 lines to regulator and -6's to carb
Jaz Cell and battery in the trunk
John Cope built HD904 with manual\reverse
Custom 3600 rpm converter
1350 joints
Moser 8 3/4 nodular center section with Richmond 4.10's and Moser Alloy axles

 

[1970Duster]

3" will be fine

 

[gtsdon]

Please let us know how these headers fit. I will be purchising a set of 1 7/8 with 3 1/2" collectors in the near future. I have been told the 3" collectors dont flow quite as good as the 3.5" collectors.