Don Terrill’s Speed-Talk

Please keep the immature behavior to a minimum! Thank you!



400+ street mill, mild gears and converter, 3450 lbs. Chevelle, tbi injected.
I may use hydraulic roller but am leaning toward a solid roller but a street design most likely DV coscam design but that is not set in stone.
I have everything in stock for a 408" build but they are hyper pistons (not really a fan anymore)
I designed these heads with a relatively tall ssr on the intake, floor wing and minimum bowl enlargement, 86% intake throat ported to 232cc with a wide pinch, 45 degree seats.
88% exhaust throat, exhaust port is small 79.5cc 45 degree seats.
I designed these for strong mid lift flow in mind, I just don't buy all llf or all hlf argument so I worked hard at keeping the flow curve thick which I think will help for a wide torque band.
I would like some input on flow curves, cam design, intake swirl,( I will post swirl graph soon), port energy, that will get us started. Thanks, Charlie

Charlie,
You sure are a glutton for punishment.

Stan

What intake will you be using the TBI on?

Sounds fun!

autogear wrote: ↑Thu Mar 29, 2018 2:27 pm What intake will you be using the TBI on?

Sounds fun!

In stock I have A few dual planes and a victor jr. tall. I was thinkin tunnel ram with dual four tbi's. I doubt any modified dual planes can keep up with the heads and a 900 cfm tb.

Stan Weiss wrote: ↑Thu Mar 29, 2018 2:26 pm Charlie,
You sure are a glutton for punishment.

Stan

I still have some self esteem left so lets go!

I would save those hypereutectic cast pistons for a cheap stock rebuild and buy some Mahle pistons with 1.0, 1.0, 2.0mm ring package. Don't make your heads look bad by using antique ring design with a ton of parasitic drag.

BILL-C wrote: ↑Thu Mar 29, 2018 6:06 pm I would save those hypereutectic cast pistons for a cheap stock rebuild and buy some Mahle pistons with 1.0, 1.0, 2.0mm ring package. Don't make your heads look bad by using antique ring design with a ton of parasitic drag.

I am with you Bill, that whole 408 kit was internally balanced and set aside for the old black work truck when the 355 died... 355 still going strong.

Those heads should support some decent rpm even on a 408 build right? 6500 deal? The tunnel ram gets my vote for coolness and it probably wins out on performance too? Will this see a dyno?

Bob Hollinshead wrote: ↑Thu Mar 29, 2018 6:59 pm Those heads should support some decent rpm even on a 408 build right? 6500 deal? The tunnel ram gets my vote for coolness and it probably wins out on performance too? Will this see a dyno?

The turbo 400 that is in it now I have set up to shift the 383 at 7000 rpm. Way too lazy to change it so 7000 rpm shift it is.

Carnut1 wrote: ↑Thu Mar 29, 2018 6:36 pm

BILL-C wrote: ↑Thu Mar 29, 2018 6:06 pm I would save those hypereutectic cast pistons for a cheap stock rebuild and buy some Mahle pistons with 1.0, 1.0, 2.0mm ring package. Don't make your heads look bad by using antique ring design with a ton of parasitic drag.

I am with you Bill, that whole 408 kit was internally balanced and set aside for the old black work truck when the 355 died... 355 still going strong.

If nothing else it would make a good dyno mule and you already have it.

Carnut1 wrote: ↑Thu Mar 29, 2018 3:00 pm

autogear wrote: ↑Thu Mar 29, 2018 2:27 pm What intake will you be using the TBI on?

Sounds fun!

In stock I have A few dual planes and a victor jr. tall. I was thinkin tunnel ram with dual four tbi's. I doubt any modified dual planes can keep up with the heads and a 900 cfm tb.

Personally, I don't think any of the readily available tunnel ram manifolds have long enough runners for 6,500 RPM and below.
Some, you can extend the runners under the plenum with fabricated spacers but, that will be TALL so. how high do you have clearance before it gets to high...?
See if you can locate an old Offenhauser "DUAL-ram", cross ram type intake; they worked really well on the street in the the earlier days.

Walter R. Malik wrote: ↑Thu Mar 29, 2018 7:12 pm

Carnut1 wrote: ↑Thu Mar 29, 2018 3:00 pm

autogear wrote: ↑Thu Mar 29, 2018 2:27 pm What intake will you be using the TBI on?

Sounds fun!

In stock I have A few dual planes and a victor jr. tall. I was thinkin tunnel ram with dual four tbi's. I doubt any modified dual planes can keep up with the heads and a 900 cfm tb.

Personally, I don't think any of the readily available tunnel ram manifolds have long enough runners for 6,500 RPM and below.
Some, you can extend the runners under the plenum with fabricated spacers but, that will be TALL so. how high do you have clearance before it gets to high...?
See if you can locate an old Offenhauser "DUAL-ram", cross ram type intake; they worked really well on the street in the the earlier days.

There used to be an aftermarket big port cross-ram type intake available for the Chevy Corvette "Cross Fire" engines from a place called "Eddie Motorsports". RENEGADE, I think they called it.
That manifold had large runners, (standard Chevrolet Corvette aluminum heads; not the extra large aftermarket runners), and an increased plenum volume. It was made for 2 single barrel throttle bodies but, I am sure the top could be machined to accept larger 4 barrel type.

EDIT: I just looked it up and JEG'S still has them available for $585.00; SUMMIT for $550.00.

GARY C wrote: ↑Thu Mar 29, 2018 7:09 pm

Carnut1 wrote: ↑Thu Mar 29, 2018 6:36 pm

BILL-C wrote: ↑Thu Mar 29, 2018 6:06 pm I would save those hypereutectic cast pistons for a cheap stock rebuild and buy some Mahle pistons with 1.0, 1.0, 2.0mm ring package. Don't make your heads look bad by using antique ring design with a ton of parasitic drag.

I am with you Bill, that whole 408 kit was internally balanced and set aside for the old black work truck when the 355 died... 355 still going strong.

If nothing else it would make a good dyno mule and you already have it.

What may happen is I will use the 383 in the Chevelle. I would rather build a nice shortblock for these. The 383 has worked up stock rods and is externally balanced. I feel they were damn near maxed out with the ported iron bowties.

Walter R. Malik wrote: ↑Thu Mar 29, 2018 7:12 pm

Carnut1 wrote: ↑Thu Mar 29, 2018 3:00 pm

autogear wrote: ↑Thu Mar 29, 2018 2:27 pm What intake will you be using the TBI on?

Sounds fun!

In stock I have A few dual planes and a victor jr. tall. I was thinkin tunnel ram with dual four tbi's. I doubt any modified dual planes can keep up with the heads and a 900 cfm tb.

Personally, I don't think any of the readily available tunnel ram manifolds have long enough runners for 6,500 RPM and below.
Some, you can extend the runners under the plenum with fabricated spacers but, that will be TALL so. how high do you have clearance before it gets to high...?
See if you can locate an old Offenhauser "DUAL-ram", cross ram type intake; they worked really well on the street in the the earlier days.

I should know what hood is on it, it looks like the bbc hood that had the flapping cowl crap. I used to run a vic jr. Tall with a 2" spacer and a 14"×6" k&n with a drop base. Just hit the hood. So I have room before I need to buy a hood. The tbi is quite a bit lower than carbs.

Walter R. Malik wrote: ↑Thu Mar 29, 2018 7:12 pm

Carnut1 wrote: ↑Thu Mar 29, 2018 3:00 pm

autogear wrote: ↑Thu Mar 29, 2018 2:27 pm What intake will you be using the TBI on?

Sounds fun!

In stock I have A few dual planes and a victor jr. tall. I was thinkin tunnel ram with dual four tbi's. I doubt any modified dual planes can keep up with the heads and a 900 cfm tb.

Personally, I don't think any of the readily available tunnel ram manifolds have long enough runners for 6,500 RPM and below.
Some, you can extend the runners under the plenum with fabricated spacers but, that will be TALL so. how high do you have clearance before it gets to high...?
See if you can locate an old Offenhauser "DUAL-ram", cross ram type intake; they worked really well on the street in the the earlier days.

I always wanted a cross ram.... Hmm. That might work nice with tbi. I actually started to build a custom top for a crossfire injection bottom crossram and two stock 550cfm tbi's for the work truck. Sold it before the move.