I just got my 400 back from the machine shop and thought I'd share my excitement.

Here's the specs of the build:
- 351M converted to a 400 - rebuilt, honed, balanced rotating assembly, etc.
- Badger .030 flat-top pistons - decked block and milled heads for about 9.1:1 comp ratio
- CompCam XE256 cam
- Edelbrock Performer 400 Intake
- Holley 650cfm carb on a 1 inch spacer (the spacer added 25 horses!)
- Taylor wires
- New distributor

And here's the engine dyno results:
- 460 ft lb of torque at 3300 RPM with a super-flat torque curve
- 340 hp at 4300 RPM.

I put the motor in this weekend and WOW!! I couldn't be happier with the performance. I'll post some pictures in my gallery when I get some time.

 

Congratulations!!! That is the kind of performace we shoot for.

 

It's amazing wat kind of numbers we can get out of them old 400's!! How much did your re-build cost you?

 

The rebuild was $2500 - this included the cam, intake, carb, etc. I also had to pay for the dyno time, engine paint, a new flex plate, carb spacer, upgraded to Taylor wires, and a new distributor. The grand total I paid to the machine shop was $3100.

I purchased about $500 in new parts: a radiator, battery, fuel pump, motor mounts, hoses, belts, fluids, etc. So far, I'm into it about $3600 and have another $350 to spend on a new exhaust system.

What's next? New bushings all around, rebuild the C6 and install a shift kit, and a limited slip 9-inch.

 

You're making me think I should put a spacer on!

Good to hear you're making such good numbers. I finally decided the break-in miles were over for my 400 the other day after I finally got my sloppy steering box replaced (with an ever-so-slightly less sloppy one), and let me tell you... I was so impressed with it when I let it rip.

My next project, I hope, will be a late-'70s Tbird with a 400. The torque is just so instant-on, but with the "standard 400 mods", you can wind it out a little and get a great high-speed experience too.

Consider me thoroughly sold on the versatility of these engines when put together properly.

 

well done. so many people bad mouth these engine. they did what they were designed to do...move big heavy objects in the dark days of emissions control.

are you running the stock iron heads? did you keep the stock valve size and just do a 3 angle valve job? cheers, garsten

 

The 1971 400 in stock configuration was a runner. Unfortunately they were neutered the very next year. The addition of a 4V carb etc really wakes them up when built close to the 1971 specs.

 

those are some good numbers, cast iron exhaust manifolds?

 

I used the stock heads but they were rebuilt with new springs, 3-angle grind, hardened guides, and new valves.

The engine was dyno'd with headers but I'm using the stock exhaust manifolds in my truck. I figure I'm losing 15-20 HP and impacting the torque curve by using the stock exhaust manifolds. But I don't have to deal with leaking headers and can use the stock air-cleaner with the heat riser (it gets cold here in MT) in the winter.

I think the increased compression ratio was the major factor. I was really going for torque when I had the motor built. I was completely shocked at the HP output. I was expecting 280-290 HP.

 

I will have to run that cam on D-Dyno to see what kind of numbers it gets and compare them to your dyno figures.

The dyno tune is really worth the money. Lots better than seat of pants work.

Are you running EGR?

 

how much did it cost to redo your heads

 

Eric - I'm using the Edelbrock Performer 400 without the EGR. Yes, the dyno was definitely worth the cost because like you said, they were able to tweak the engine while it was on the dyno - in fact, that's how I ended up with the carb spacer - they tried it out and it was a definite improvement.

I'm not sure what the exact cost to redo the heads was - it was included in the total rebuild cost.

 

What distributor did you use and did you have to tweak it any? Are you getting any pinging under part throttle due to the lack of EGR?

 

Jason...see my pm please.

Also wondering what model Holley you have. Thanks

 

Eric, I'm using a remanned distributor. Great question about pinging! It pinged so bad with the vacuum advance hooked up it was almost undriveable. I'm running without the vacuum advance now and there is no pinging at all. The mechanical advance is working just fine. My initial timing is set at 12 degrees BTDC.

I'm taking it in today to have the machine shop tweak the timing and take a look at the vacuum advance issue. I may end up with a recurved vacuum advance - or no vacuum advance at all. I'll let you know.

Roger, I'm using a remanned Holley built by QuickFuel Technology (the 650CFM HP series - www.quickfueltechnology.com).