Ok, I am building a 400 SBC for my 68 Camaro Bracket car.
I am looking for the most power I can get on pump gas. I would like input on Cam, Carb, and Torque Convertor for my application..

Spec:
400 2 Bolt .040 over = 408 CID..
Eagle 4340 3.75 Crankshaft.
Eagle 4340 H-Beam Rods 6.0 inch.
SRP -5cc dish Pistons for 10:1 with 64cc Heads..
AFR 210cc Aluminum Heads 2.08 int - 1.62 exh valves.
1.60 Proform Roller Rockers.
Victor Jr Intake

The vehicle is a all steel 68 Camaro with TH350 Trans and a A1 3000 Stall with 4:56 Gears and ladder bar suspension..


What cam would work for my setup? Also how big of a carb should I be looking at..

I want to go 10's with this motor, Is it possible??

Thanks for any advise..

 

You can go a LOT higher compression and still run pump gas with aluminum heads. A friend of mine just built this engine which is a 408 sbc:






I know he's easily in the mid 500's just on motor. This engine was pushing 525hp at wheels and was running in the 10's in a 72 Camaro. He rebuilt it just a few weeks ago and when he installed it it was a world of difference. His old engine wasn't nothing to shrug at but this one is a friggin' beast.

Here's the parts I do know:

64cc aluminum Pro Topline 235cc heads
670(ish) mechanical roller cam
1.6 Crower roller rockers
forged lower assembly
Edelbrock Victor Jr intake

Those are the main things that I remember off the top of my head. I know he's in the mid 11's as far as compression ratio without a single problem. With the larger duration cam and the overlap it helps with the compression ratio.

There's a few of us going to the dyno in the coming weeks and he's taking this one when he's gotten the break in done. This is his daily driver also fwiw and he drives it everywhere.

 

Max compression on a pump gas engine is 10.5 to 1(93 octane). Take a look at the Brodix ik 200 heads look like a heck of a head for the money. The 408 on the street is a great combo.....

 

You are over 10:1 with 64cc heads and -5cc pistons I think - believe you need -16cc to be 10:1 - but with aluminum heads or a wild cam you will be ok on pump gas - I would use a Scat crank instead of Eagle crank - Eagles have lots of comments on grind quality being poor. I think you might want to get splayed caps if you want to get into the 10's - I'd go with a roller cam for your best HP/Torque.

 

I had recently changed the worn out heads of my car to put sbc aluminum heads. the overally performance has increased to a great extent and the overall expense has been worth it. the compression given is also good.

 

I agree with Srode on your CR. I would be busy reading the plugs if I were you because lean is mean when you're pushing that much compression. The more duration you put in the better you will be on avoiding detonation to a certain point. I would think you will want at least 270 at 50, maybe more. I switched from a 750 Holley dp to an 850 Holley to an 850 Quick Fuel and every time the car picked up, so I would guess a well tuned 850 would probably work for you. Your build sounds like fun, good luck with it.

 

My machinist has had problems with Eagle products and doesn't use or recommend them at all. He flat out told me not to use them at all. The guy that owns the machine shop that does all my machinists balance work (they're been doing business together over 20 years) told me the same thing. I went with Scat on both of their recommendations. My engine isn't an all out race motor either, it's a mild street performance engine or they may have recommended different parts altogether. Just my $.02.

 

If I was considering building a 400 to go into the 10s I would really consider an aftermarket block like the Dart http://www.jegs.com/i/Dart/301/31161211/10002/-1?CT=999 If you are using the factory block have the bores sonic checked, I would also consider deck plugs, studding the block. About the spark plug reading, it really needs to be done in the wide open thottle immediate shut down method I have found it difficult to read the plugs when using the pump unleaded fuel with all the cleaning additives the fuel ratio sensor always seemed like a better idea I just havnt put the cash down for one....

 

My thoughts on cam selection for your build are to keep the comp. no more than 10.5, and yes alum. heads do allow for more compression, but at 408 cubes, any more comp. and your pushing your luck. I see no point in going with solid roller cam, as your comp. range and engine size won't allow the use of a cam in the 600 range without murdering the bottom end torque range, and your car is certainly not considered a light weight that can afford the loss of bottem end. You certainly could go solid if you wanted to keep the 4.56 gear in the car, but that gear would not be good for the street. How about a hyd. roller in the 5.60/5.80 lift range. It would make all of it's power at around 6,400, and the 4.56 would not be needed. Go with a 3.73 if you wan't to cross the line at the track, but you will then be exceeding the peak power rpm even then, as you would be crossing the line at around 6,800 Truth is a 400 engine in a car that's around 3,250 can't be optimized for both street and track. If a good et means a lot to you, then go with a solid roller in the 6.00/6.20 range, and keep the low gear in the car, but go up to 3,800/4,000 stall. The car will be more like a Pro-Street setup, and in my opinion a blast to drive on the street but no long jounts on the highway. You have the right heads, and they will work with just about any cam you wan't, and the 400 engine with the 6 inch rods are a supurb match. If you favor running on the street, and highway, and want more streetability, then go with the hyd. roller, a 3.73 gear, and the 3k stall will be fine. A carb in the 950 range is a must regardless of what setup you go with. I know there are plenty of 850's floating around, but that will cost you on the top end, but if you do find a good deal on an 850, the one good thing is it will have better street manners than a 950. As for the Eagle crank, well if it's a 4340 then it's far more than your engine will ever need. Be sure and check the journals very closely for divets/scuffs. As for the Eagle rods, they rein supreme in that department. As far as offsetting to much compression with cam selection, I'm not sure if it's the right thing to do. Are the parts you mentioned items that you now have or are considering buying new? If you go with the hyd. roller setup then there will be no need for the splayed caps, but the solid roller setup spinning at around 7,200 should have splayed caps. The 600/620 cam will actually make all of it's power at around 6,700-6,900 You most likely will never see 10's with either setup, as your car is simply to heavy. To see 10's you would have to put the car on diet, and build up to around 11:1 and optimize your suspension, and of course spike your fuel at around 50/50 It's just hard to see 10's with your setup, but you would be on the heels of it. By the way, mid 11's comp. range in a somewhat heavy car such as the 72 Camaro is positively not able to run on prem. pump gas, and if you detuned it to run at this comp. range, then I highly doubt it would run in the 10's on pump gas. In the dead of winter, with no heat soak, still not on pump gas. Checkout dragtimes.com and it can give you a lot of good ideas on what it takes to break into the 10's all things considered. My last sentence was in refference to Kyphur's post on the engine his friend built. I was not sure if he was recommending such a build for the street to run on pump gas or what, but that engine may certainly run mid 10's at the track with straight high octane race fuel, and go home on the back of a trailer.

 

Nope, the car is strictly street and he never has ran race gas in it (at least when I wasn't around). He drives it to and from the track at over 30+ miles away and usually has around 5 - 10 runs depending on the day/night. Here's a link to it and the 10.99 time is before the new engine and that was with his old 383. Unfortunately he just sold it and the guy who bought it turned around and pulled the engine and transmission and sold the body.

If you're the Skip White out of Tennessee with Skip White Performance I know who you are. I've think I've even referenced you a couple of times for 400 sbc builds on here with your little Datsun. I think I've even bought stuff from your business.

I'm running 10.75:1 compression with a solid roller cam at .603/.610 and 274/280 duration and have no problem with a low end or a high end. With my 3.42's though I have problems with highway speeds being manageable with my T-56 (shifting at 90mph to 6th gear and it settling at 1800 rpms). That's the only reason I'm considering a 4.56 gear. I would ideally a 4.33 but I'm just not finding a set for the price I like or can get a 4.56 for brand new.