[twov8sandat4]

Hi all,

I would like to know if it is possible to improve my setup with a cam upgrade. The current setup on my 74 T/A is as follows:

- Original 400, 4x heads (unported, 8:1 comp.), TH400 with stock converter, and 3.42:1 gears.
- Edelbrock RPM with Shaker455 built 750DP and Carter mechanical fuel pump.
- Hedman 3-tube headers with 3" Pypes Race Pro setup.
- Total weight with me in in is 4022 lbs. Tires are 255-60/15 BFGs.

The motor was rebuilt by previous owner in 1988 to stock spec.s with the exception of the cam. It has a Crane cams HMV260-2-NC (part # 283901,) with 260/272 advertised duration, and 204/216 duration at 0.05 lift. Best et to date is 13.91 @100 mph. The motor is lazy getting up in the RPM range and runs out of steam around 4500 rpm. Jeff (Shaker) did confirm that my HEI was junk and needed to be upgraded, so that is on the list of things I want to address also.

The hangup is I want to leave the engine/drivetrain as is. I don't want to pull the motor out for a rebuild or send the heads out for porting. I am saving my pennies for a future IA2 based build. For now, I am interested if a cam swap is worth the effort. If so, what would you recommend? If not, I'll leave things as is.

Also, would I benefit from upgrading the crappy 3-tube headers to the proper 4-tube headers?

I did a lot of searching, especially in the engine combo thread, but had a hard time finding a combo like mine to compare to.

Hope this makes sense, and thanks for any help

[David Jones]

If it were mine the RPM and probably the Holley would both go. The RPM is not suitable for the engine combo you have now. A regular Performer or stock, late 60's early 70's, cast iron intake and a Qjet would replace them. The 3" exhaust is killing you also. You waaaaay don't need that. A 2.25 or 2.5" system would serve what you have now better. Both the RPM and the 3" exhaust are killing your bottom end....and send that HEI to SunTuned.

[twov8sandat4]

Originally Posted by David Jones

If it were mine the RPM and probably the Holley would both go. The RPM is not suitable for the engine combo you have now. A regular Performer or stock, late 60's early 70's, cast iron intake and a Qjet would replace them. The 3" exhaust is killing you also. You waaaaay don't need that. A 2.25 or 2.5" system would serve what you have now better. Both the RPM and the 3" exhaust are killing your bottom end....and send that HEI to SunTuned.

I actually obliterate the tires on any launch RPM above idle with this setup, it is up top where I am having problems . The cam card says 1500-4000 RPM range, and sure enough that's where it starts to flatten out .

I actually picked up almost 3/10s and 3 mph swapping from the Performer (non-RPM), 650 DP and 2.5" Flowmaster setup, to the intake/exhaust combo I have listed above, so my two brain cells say I is headed on the right track, but I don't know

I was actually able to score the correct, date coded, intake and carb (even though they are not as desireable as the earlier intakes) for the car, so at some point down the road (carb needs complete overhaul) I might swap to those if needed.