[brodad]

Hey guys, I am building a 400 for my 64 Lemans here’s my info so far.
400 30 over
stock stroke
#16 head ported to 240 cfm with Comp Cams 995-16 springs (I bought these as they are)
14cc dished pistons 9.5ish compression
forged rods
SMI quadrajet
Edelbrock RPM intake
Ram Air Restoration exhaust manifolds with 2.5” exhaust pipes
TH350 trans to replace the ST300
Unsure of rear axle ratio
27” tall tire
Car will be full weight and will be primarily a cruiser.
Power brakes and a/c
Please feel free to suggest anything I’ve missed or direct me to a thread I’ve searched and am still confused.
I have seen the Summit 2801 and Lunati voodoo 702 come up several times.
Thanks for your input and patience.

[ponyakr]

Well, at 240cfm, you can put some cam in it & wing it, if that's what you want.

No reason to go with less than a Summit 2802, unless you just want a smooth idle and plan to run a stock converter, and highway gears, like 3.08 or numerically lower.

With 9.5CR or more, you don't really need a Voodoo, IMO. But some here like a Voodoo for almost every application.

Here are some cams similar to & slightly bigger than the 2802 Summit.

https://www.summitracing.com/parts/c...IaAusEEALw_wcB

https://www.summitracing.com/parts/hrs-410141-12

https://www.summitracing.com/parts/c...kaAv4oEALw_wcB

https://www.summitracing.com/parts/c...w/make/pontiac

https://www.summitracing.com/parts/h...w/make/pontiac

Next up would be some version of an 041 clone, such as a Melling SPC-8. But, I wouldn't use it in a 400, without Rhoads lifters. In fact, I'd use Rhoads on most of these cams, in a 400. If you don't use Rhoads, at least use the Hylift Johnson "R" lifters, sold by Paul K here. They're said to bleed down some, just not as much as Rhoads.

https://www.facebook.com/PaulKnippensMuscleMotors/

Lots of guys have been disappointed with an 041 cam in a street 400. For street cruising, & under 5000 rpm operation, I'd choose something smaller, even tho 240cfm heads will flow enuff for higher rpm operation. Don't really need that much flow, for under 5000 rpm operation.

Your main rpm range, converter stall, & rear end gear are big players in what the best cam would be for your application.

Some say around 220° @ .050 is plenty for a mild street 400. My 1st choice in this range is a Lunati 10510312. Should have a fairly smooth idle, plenty of vac, lots of low end torque, & should make decent power to aprox 5000 rpm. But, it's much too small & mild for many on this forum.

https://www.summitracing.com/parts/lun-10510312/

Anyhow, that's my opinion. You'll get others, after some of the other guys wake up.

[steve25]

I don't see you having a 9.5 comp with those numbers.

If I assume a at best 72cc number for the chamber in those heads if they have not been milled, and zero deck height on your .030 " over motor, I come up with 9.14 to 1.

And this is without factoring in any CCs for the ring land volume also!

Piston volume of 4.150" Bore 400 = 831.17 CCs.

Total volume above piston=

72+ 9.4 cc heads gasket+ 14 cc dish+ 6.7cc valve notches= 102.1 CCs

102.1 + 831.17= 933.27


933.27
-------------- = 9.14 to 1.
102.1

[OCMDGTO]

My old engine/current spare was very similar. Ran very good on the street for 11yrs/30k+ miles and a best of 12.90 @105 w a 1.9 60' time:
400 .030 over, 16 Heads w stock flow but intake was port matched to RA 4, 750 Holley, Torker2 w 1" spacer, Comp HR288 (236/242D, .520/.540L), T400 w 3500 stall, 3.23s & 3.50s both used, & Ram Air 2.5" manifolds

[steve25]

Sorry, you would not want to run more then .600" lift to be .050" away from coil bind.

[b-man]

You really need to figure out what rear end gear you have to choose the right cam.

It’s pretty easy:
https://forums.maxperformanceinc.com...77&postcount=5

[Stan Weiss]

Originally Posted by steve25

I don't see you having a 9.5 comp with those numbers.

If I assume a at best 72cc number for the chamber in those heads if they have not been milled, and zero deck height on your .030 " over motor, I come up with 9.14 to 1.

And this is without factoring in any CCs for the ring land volume also!

Piston volume of 4.150" Bore 400 = 831.17 CCs.

Total volume above piston=

72+ 9.4 cc heads gasket+ 14 cc dish+ 6.7cc valve notches= 102.1 CCs

102.1 + 831.17= 933.27


933.27
-------------- = 9.14 to 1.
102.1

Steve,
Your math is correct. But I am not sure that you are counting some area twice. From what I have seen some times some of the valve notch area and the dish is the same. A picture of the piston top would help here.

Stan

[1funride]

2801 is a small cam, too small. My engine is about the same as yours, I have 3.42 gearing and 2500 stall. My bullet cam is a good street cam, with a mild idle, and makes lively power everywhere from idle to 5400, it will run out a little more but is basically done by 5400. Good street cam.

[steve25]

Well your right as I am assuming aftermarket Pistons with 6.7 CC notch volume , but even if he has factory cast Pistons made before late 1974 then he may have only 5 CCs of notch volume, but that change is still just shy of bringing him to 9.5 to 1.

[Cliff R]

Pretty much a waste of time/funds to have the heads ported to 240cfm and install an RPM intake then put a tiny little cam in it. To take advantage of that much head flow you need to be look at much larger camshafts that will push peak power up over 5500rpm's or so. Dropping the compression didn't help the scenario as larger cams needed to effectively use that much head flow are going to be happier with another full point of compression or so.

Otherwise you might as well have left the heads stock, dropped compression to 9.5 and went with the 2801 cam. That's actually a pretty nice combo, idles well, strong power at lower RPM's and pretty much done around 5000rpms......Cliff

[blueghoast]

Originally Posted by Cliff R

Pretty much a waste of time/funds to have the heads ported to 240cfm and install an RPM intake then put a tiny little cam in it. To take advantage of that much head flow you need to be look at much larger camshafts that will push peak power up over 5500rpm's or so. Dropping the compression didn't help the scenario as larger cams needed to effectively use that much head flow are going to be happier with another full point of compression or so.

Otherwise you might as well have left the heads stock, dropped compression to 9.5 and went with the 2801 cam. That's actually a pretty nice combo, idles well, strong power at lower RPM's and pretty much done around 5000rpms......Cliff

I would listen to Cliff, The man knows his stuff.

GT.

[OCMDGTO]

I should have added Cliff had a GREAT thread about 400/iron head builds with Crower hydraulic flat tappet cams you should search for

[Stripes]

Save your money and run a port matched stock intake and make more power than the performer rpm.

[Jay S]

Didn’t the t300’s usually have a tall highway gear behind them?

I think someone else mentioned it. Really should know what the gear ratio is to help pick a cam out.

If it does have a highway gear I would take a hard look at the summit 2801 with some 1.65 rockers. Or some cheaper melling ra4 rockers to let the engine breath better and make for a decent running cruiser. That 702 Voodoo would be ok too. But even with 1.5s on it you likely need to adjust the seat pressure of the springs, those lunati’s and some of the later designed Ultradyne profiles like 130lbs. 995s unless they are set up for 130 run less than 120. Some are closer to 100 after they get some time on them.

If it has a 400 and a decent gear ratio, 240 head flow and 9.5 compression, with the RA manifolds: imo... you really can’t go to wrong on those cams around 220. @. .050 with the 112 and 114 lsa’s. Even the 2801 with the 1.65s has an effective duration close to that. I have seen some decent performance gains from some head porting with smaller cams. But it makes more of a difference with those high rocker ratios. We have been using a lot of Ultradyne cams. So I am a little biased there, but am not afraid of any of those cam Ponyakr list in post 2. FWIW, The crane 276 cam is a really good cam with the ra manifolds. It is more modern profile than the summits, even though on paper it looks nearly the same as a 2802.

Figure out your gearing....