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Discussion Starter #1
Little background first. This engine has exceeded my expectations in N/A form. It made over 500 to the tire and has gone 10.0’s at 134 mph in my 3000lb car with a DR4 transmission. It is 321” has Vic jr heads and manifold. Now with the twins it will be 10.5:1 blow thru E85 CSU 750 dual needle carburetor. Cam is a comp billet TC lobe on intake and exhaust 275 @ .020 244 @.050 with a .428 lobe lift 115+3 and 1.7 rocker. I have twin S366 turbos and there will be no Intercooler. I am looking to make 1000 to the tire.

What spark plug would you use for this combo? What rear gear? Transmission will be a proven C4 that has been 5.0’s many many times in a different heavier car. How fast is this combo capable of going? I have had nitrous combos blower combos and N/A this will be my first turbo setup. Thanks for the input.
 

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C4 won’t last, I ran a similar combo and made 1070 tire on 20# at 15* timing. Was using 3.90 gears with a glide. I would still worry about air intake temp without an intercooler. Text for details and pics 3862168593. Can’t load pics here.
 

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Discussion Starter #8
C4 won’t last, I ran a similar combo and made 1070 tire on 20# at 15* timing. Was using 3.90 gears with a glide. I would still worry about air intake temp without an intercooler. Text for details and pics 3862168593. Can’t load pics here.
Thanks, I will send you a message. I have been thinking more and more about a glide.... I would be happy with anything between 850-1000 at the tire.
 

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.730" lift? That's a lot more then you need especially with a 242 deg at .050" duration cam. I would start with some 1.5 rockers and change to the 1.7s if unhappy. Try letting the boost do the work first.

Just to give you more info, my cam has the same duration and only .590" lift and uses hydraulic rockers. My seat pressure is only 160 lbs. Much easier on valvetrain parts. 3550lb car that has gone 8.23 at 168 mph.

10.5 comp ratio and no intercooler will limit your timing even with E85.

Overall I'd say you'd be better off with 1.5 ratio rockers and an intercooler.

My car is street/strip so I like to use NGK Iridium plugs, 8EIX? I can verify the plug if you're interested but I use those mainly because they last forever and I want to change plugs regularly.
 

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Discussion Starter #12 (Edited)
.730" lift? That's a lot more then you need especially with a 242 deg at .050" duration cam. I would start with some 1.5 rockers and change to the 1.7s if unhappy. Try letting the boost do the work first.

Just to give you more info, my cam has the same duration and only .590" lift and uses hydraulic rockers. My seat pressure is only 160 lbs. Much easier on valvetrain parts. 3550lb car that has gone 8.23 at 168 mph.

10.5 comp ratio and no intercooler will limit your timing even with E85.

Overall I'd say you'd be better off with 1.5 ratio rockers and an intercooler.

My car is street/strip so I like to use NGK Iridium plugs, 8EIX? I can verify the plug if you're interested but I use those mainly because they last forever and I want to change plugs regularly.
I have 1.7 T&D shafts on the engine currently and the springs on the heads PAC 1225’s are almost new and ironically the N/A cam in it now has the exact same lobe lift so the heads are set up for that amount of lift. Does it need all that lift, probably not, but it makes it much easier not having to change the installed height on the springs.

This engine has 100+ passes on it naturally aspirated. See’s 9,000+ rpm every pass, so the valve train has been proven to be stable. The turbo cam will only go about 8,000. I do understand what you are telling me tho and if I didn’t already ha e the t&d’s and the heads set up with the pac springs for that lobe I would probably tone it down some. 850-1000 HP I will be very happy. Made 505 to the tire n/a.

I am interested in the iridium plug.
 

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Discussion Starter #15
That is too small for a non ball bearing turbo. Borgs need atleast -4 feed.
Gotcha, I have -3’s plumbed to the valve covers with internal spring oilers. I was going to use those lines as I don’t need them anymore. I had the rockers updated with oilers in them. I will get some -4 lines and fittings.
 

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Anyone ever run the oil return into the timing cover on a sbf?
I wouldn't suggest it. The drain back holes in the heads are already overwhelmed.
 

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Discussion Starter #18
I don’t honestly believe that the front drains do much of anything while going down the track. It is weird how some have issues on oil return through the heads and other so not. I have never had an issue nor have I been around one that has. Other than a few BBC’s never a sbf. Even with oilers in the covers.

I was just looking and thinking about routing the returns and thought it may be a good option. Lots of LS guys run it in the timing cover. I just want to keep it as far away from the crank throws as possible.
 

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Discussion Starter #19
I am still not 100% sure where the turbos will be, I want to try and keep the radiator in the stock position.
 
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