This swap to the Indy SR heads delivered a knockout punch beyond our expectations. Imagine the difference if we had tested them against a stock set of heads, either 906 or 452 castings. Moving to a more aggressive cam and a bigger carb would have surely given us a mid-10-second, pump-gas street car. Of course, for now, that's merely speculation. If you decide to use Indy heads on your B/RB, be sure to plan your combination wisely and don't try to put these heads on a low-compression motor and expect big gains.
Indy SR Heads Flow Chart
As tested at Ray Barton Racing Eengines SF-600 Flow Bench
|Port & Polish|
|Port & Polish|
With Back Cut and
|Lift||Stock||Ported||Ported & Polished|
Note: Indy sells the SRs with optional CNC super-modified porting with the Max Wedge-size intakes. It will save you many hours while returning flow numbers and performance equal to, or better than we achieved.
Chassis Dyno Results
Superflow SF840 SAE-corrected rear-wheel horsepower and torque tested at SLP Performance Parts & Engineering Center
|Baseline W/906||Indy w/40 Timing||X Stream||Wilson Space|
|Max hp @ rpm||366 at 5,600||433 at 5,600||433 at 5,600||433 at 5,600 |
|Max tq @ rpm||427 at 4,200||457 at 4,200||460 at 4,200||465 at 5,600 |
|Avg hp @ 4,000-6,000||350||394||397||403 |
|Avg tq @ 4,000-6,000||367||410||414||421 |
Here's a before-and-after look at the headers and exhaust. (A) The production-headed 440 h
(B) The TTI headers (for Indy heads), feature 2- to 2 1/8-inch primary tubes into 3 1/2-in
On top of the Wilson Manifolds box is its famous strip- and engine-dyno tested, four-hole,
We tried leaning and richening the air/fuel mixture, but went back to the original jettIng
A gear change from 3.55s to 3.91s was a logical choice to take advantage of the wider, str
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