[joedls]

Originally Posted by Vettezuki

Cams?

See pic above

[94cobra69ss396]

Originally Posted by Vettezuki

Just FYI,

I'm pretty much striking out everywhere I look for 174 parts, and the blower services aren't getting back to me. I would be interested in going NA if the 174 doesn't work, but if we do, I'd like to make it kinda gnarly by going to a nasty solid cam/lifters (would also have to change springs since they're being setup for the mild hydraulic blower cam we have now). I think this is pretty much what Ron and Bird had in mind. But the big thing I'd like to try in this case is to go E85. That would be our challenge as well as our little talking point. I'm guessing, but an aggressive E85 tune (cool charge, 105~ octane) on a high spinning big cam, LT headers, etc. should be good for hi 300s maybe even crack a 400 to the wheels on the 306. We could also keep the IRS and that plus not having the blower means the car would be quite a bit lighter, maybe down to <=2,500lbs.

I think the hydraulic roller springs will work fine with a solid flat tappet. They usually have a higher spring rate for heavier weight of the lifters but that will work well because we need more spring pressure for the higher rpm.

Check to see what the open and closed spring rates are when you pick up the heads. Also check to see what the max lift he says you can use. We can check to see what the cam manufacturer recommends for the cam we want to run and compare.

I'm also not using the springs that are recommended for my cam. I'm running a solid roller that needs more spring pressure with springs designed for a flat tappet cam but because I only turn 6500 they worked fine. I accidently over rev'd the engine doing a burnout when I first put it together and hit valve float at 7200. Now after 2 years of racing the engine stops pulling after 6000.

[BRUTAL64]

Originally Posted by Vettezuki

One. FMI, knowing what cams would you recommend.?

Ok, what rear gear are WE going to run? Are you thinking flat tappet or solid roller??


Just thinking tunnel ram with TWO 500 performers or 360 Holleys.

[94cobra69ss396]

Originally Posted by BRUTAL64

Ok, what rear gear are WE going to run? Are you thinking flat tappet or solid roller??

I would say flat tappet due to cost.

[Vettezuki]

Originally Posted by BRUTAL64

Ok, what rear gear are WE going to run? Are you thinking flat tappet or solid roller??


Just thinking tunnel ram with TWO 500 performers or 360 Holleys.

The axle we have is a 4.1. I'd run a fairly short tire (26~) for aesthetic reasons. That means this little mill would need to spin to reach higher speeds.

Why two carbs? What's the theory?

What's the real difference in cost between flat tappet and solid roller? What's the performance "hit" for flat tappet vs. solid roller if the intent is to spin the hell out of a 5L? Also what about durability and maintenance? I don't know much about this subject, but does a solid roller setup require regular tweaking because of the lash with the lifters? Sorry, I just don't know much about this detail of engine internals.

[Vettezuki]

Originally Posted by joedls

See pic above

Sorry, I'm behind a firewall and couldn't see. Had to "step outside". This looks awesome . . . and expensive.

[BRUTAL64]

Originally Posted by 94cobra69ss396

I would say flat tappet due to cost.

Here's a start:


# 31-641-5 600 I 593 E lift Dur at .050- 265 I 276 E with LSA of 106.

This, of course is just a guide line.

[BRUTAL64]

Originally Posted by Vettezuki

Why two carbs? What's the theory?

Well, the "WOW" factor and better balance for each runner on a Tunnel Ram.

One barrel for each port. KINDA like FI.

Cost for a cam kit in Solid lifter is much better than a Roller by about 4x.

[Vettezuki]

Just picked up the heads. I'll put up some pics later. Because the first castings that were sent out were the wrong ones they threw in some bowl work, whatever that means.

SPRINGS
Seat Pressure 150lbs.
Open Pressure, he said he couldn't give an exact number without knowing the exact cam, but based on what I told him (.540 lift, hydraulic roller) he said high 300s low 400s max.
He said they'll safely support .700 lift

BASIC CAM RECOMMENDATION
He said we could run a solid flat tappet with these springs, BUT unless we were going to port the heads and were willing to be careful with break in and do maintenance, there wasn't really that much advantage. He recommended sticking with a nice big high lift hydraulic roller and be done with it for simplicity's sake. Basically it's the point of diminishing returns.

[Vettezuki]

What are the blower dynamics of the MagnaCharger MP112 vs. the Holley 174?

As I mentioned earlier, there is a seller on eBay that has brand new MP112 carburated models for $500 (just the blower, no intake or pulleys). Pacific Performance, where I got the heads, actually made and apparently still has in stock a couple offset Dizzie drives that take an MSD cap. They were specifically designed to give clearance to Roots blowers on 289/302 SBF. We'd have to modifiy an intake or create and adapter for the MP112, as well as figure out front drive, but this is possible. Just throwing it out as an option. I'll call PSE on Monday to see what they can do with the 174.