[raj]

A friend of mine has a 400 in a late 70's firebird. I've only talked to him on the phone about this car since he lives about 2 states away. He never gave me the year or head casting number on the engine but from what I can tell it's about a 1970 or so 400 from a big car since it has a 2bbl carb.

He wants to make some simple mods without pulling the engine such as gearing, more exhaust, an Edelbrock intake and a cam. I mentioned the 2801 Summit cam would be a good choice but thinking about it, the heads probably have press in rocker studs. For a mild build like this I'd figure the press ins are OK, but what do you guys think? What would be a good choice for this engine(or any) with low compression and press in studs? I realize the right thing to do would be to pull the whole thing and go through it with the right pieces but he doesn't want to do that.

[smagnotti]

It really depends on how much more spring pressure he will have. Myself and forom my use of heads with pressed in studs, anything close or over a 40 lb increse, than its time for screw in studs!

[SWEETJUDGE]

anything close to .500 lift (.490 or greater) you will need screw in studs..... use big block chevy 7/16 ARP

[70lemansport]

I think that at either had #11 or #16 small valve heads(if indeed they are 1970 peices). That gives him a CR of either an 8.6 with the #11's and 10cr with the #16s. From what ive learned here a CR of 8.6 is great for the street and a CR of 10 is too much. either way not the greatest heads but decent for a street car. Im putting that same cam in my 350 with the 350#11 heads and i can't wait. ( it could have #12or13 heads maybe too. but those were for 4bbls i think..)

[raj]

I forgot about the springs. How would this cam perform without stiffer springs?

Like I said I'm not sure on the year but with a 2 barrel, I'd figure it wasn't too special from the factory. Hey Sweetjudge, what's the part number for those studs and would the accept stock rockers? Just curious.

[70lemansport]

Stock springs are ok to about .470 lift( or come to think of it maybe its .460? maybe someone can clarify). Any more is not good for them. i replaced my stock springs with new stock spec ones(i got them for free) just to be safe.

[smagnotti]

The stock springs will take .470" lift and if in good condition(unliky) rev to 5000 to 5400 on a non stock cam lobe.
You CAN pump more lift into the stock springs, but if they are not too worn now, they WILL be in short order!

[BVR421]

I put a 2801 in my 63 389 Cat w/2.69 gear, about 8 years ago along with new stamped rockers, lifters, timing chain. Factory press-in 3/8 studs with Crane Kool Nuts. 3/8 lock nuts would have worked as well. I bracket raced weekly (weakly) one whole season and as daily driver at the same time plus 10k out of town trip miles. Honestly I dont know if the car was any quicker due to the cam change. I do know the full dual exhaust made the most difference, even more than when I switched the 2brl to a 4brl. When I had the qjet on there it got better mileage than the 2brl. Best times (high 16s) were shifting at 5k though it would rev eagerly all the way to 6k if I let it.
NO PROBLEMS using the factory pressed studs and 100k valve springs.