Lepine Bob

Hi , im a french canadian, sorry for my writting mistakes... so heres my question..
i just bought an 1985 c4, with the 350 tpi
i was building a 400sbc wich im planning to put in next summer,
i was wondering if the cam i choose is to big for the street and my next question is wich intake should i be looking into or should i just do a porting on the tpi. Budget is not in consideration.
heres the mod i currantly have for the 400

sbc 400,
lunati double timing chain
scorpions aluminim heads 64cc exhaust 210cc intake
msd distributor and ignitions
procomp 1.5 roller rockers
high volume oil and gas pump
LUNATI STREET MASTER CAM

• Advertised Duration (Int/Exh): 295/295
• Duration @ .050 (Int/Exh): 245/245
• Gross Valve Lift (Int/Exh): .534/.534
• LSA/ICL: 108/104
• Valve Lash (Int/Exh): Hyd/Hyd
• RPM Range: 2500-6500

3.73 or 4.10 gears
700r4 transmission
295/55r15 et street mickey thompson

so is the cam too big ? And what do i do for the intake set up?

thanks for your answer

cv67

If you HAVE to have a TPI look into the FIRST system, that intake was designed for a 305...even a ported one is still choking a healthy 350
(yes that cams way too big for a LTR intake)

What heads?


Do you need to pass emissions, some kind of visual inspection? Can you run headers?


you got a pm

Lepine Bob

1 1/2 intermediate flowtech headers
no i dont need to pass an inspection
wich intake would be a perfect fit with those heads and this cam

cv67

1.5 primaries are way too small, step up to a 1-3/4" primary long tube
A single plane would be awesome if you can figure out the EFI dont know anything about tuning them but guys do it here a lot
with 4.10s a nice converter it will rip good

You have plenty of cubes for torque no need to add "small" parts to pick that up your biggest problem will be wheelspin

383vett

That cam us way too large. My 406 strip only car has a smaller cam. With the TRI and the 104 108 lsa this would be a really bad combination with your tpi.

Tom400CFI

Was friends w/a guy who had a 400 and a similar cam, with a ported Miniram, AFR 195 heads...it was too much cam. He went down to a smaller cam (23x@.050 range, IIRC) and the car dyne'ed higher and ran the 1/4 mile faster. And it ran way better on the street.

blackozvet

that Lunati cam is a carby cam, too much duration and too tight on the LSA at 108 for EFI.

The biggest issues you face with the 85 is the '870 computer and the TPI. Both those things will cause performance headaches - especially on a big cube engine.

you could go carby and use that cam - that would eliminate the above issues.

or if you want EFI consider the new self tuning options out now, there are quite a few, Holley, MSD, FITECH, etc. using a 4 barrel throttle body on a single plane intake, where the computer is built into the throttle body or attached.

ghoastrider1

Edelbroc has came out with a new manifold for the TPI, cost 500 bucks and is good for a 350 but not sure about a 400. Good luck getting the computer upgraded for that .

Tom400CFI

Bigger cubes ought to help the tuning situation, IMO, since it makes the cam "seem smaller". While the '85 ECM isn't ideal compared to today's stand alone systems....I certainly think that it's workable -especially w/a reasonable cam.

vettespecial

I once owned a 84 Montecarlo SS that i dropped in a 400 into with a large cam like yours 373 ratio in the back, a holly 750 on a Eddelbrock
intake it was a torque monster! my 90 L98 rebuilt SB 355 with a ZZ409
cam, would never come close to the power i had in that beast back in 88,
I i had a 400 today for my vette i would go with the holly carb set up only! No TPI. no problems.

Lepine Bob

What if I go EFI
https://www.summitracing.com/int/par...0500/overview/

no ecu problem , no tpi problem , would this be a great match ?

cv67

https://www.summitracing.com/parts/sne-550-510