377

i have a short block with a gm steel crank pink rods trw forged pistons . need rings and bearings. the block is 010 4 bolt main .i have a gm duel plane manifold lt1. not sure on using headers. exhaust is 2.5 with x pipe. trans is 400 26 to2800 11" convert. rear is 355 ratio. need help with what type of rings/bearings? cam roller or flat tappet lift? heads looking at iron heads what size intake/ex want to make 350/ 400 hp and all the tq i can make red line 5500/6000 rpm. not building a race car want to keep up with whats on the street thanks

ajrothm

I just built basically the same combo you are building. I did not dyno it and the car is not driving yet, but here is what we did for my dad's 70' SS 350 Nova.

#s matching 350 block bored .040 (357")
Stock crank turned .020/.020"
Sealed Power forged flat top pistons, 4 reliefs
Stock rods w/ ARP bolts, resized.
Should be around 9.7-1 compression assuming the pistons arent buried at TDC...(we didnt square deck the block so we wouldnt lose the stamps)

Original/#s matching 1.94" double hump heads, 3 angle valve job/surfaced, no porting. Screw in studs/guide plates. 64 cc

XE268 Comp HYD flat tappet. 224/230*
Performer RPM intake
Holley 3310 vac secondary (750 cfm)
Hooker 1 5/8" x 3" headers.

I'm hoping this combo will make an honest 350hp...No doubt, the heads are holding it back a good bit but....

T350 trans, Hughes 2500 converter, 3.55 gears. 2.5" exhaust w/2 chamber Choke/Flowmasters

I figure it should dip into the 13s pretty easy....Should be enough for a 65 year old fart.

Les

Alan,
If/when your Dad's Nova is finished, would you mind posting some photos of it? My brother had a '69 Nova SS that I loved and still miss. It would be a treat to see another one so I could take a little trip down memory lane.

GOSFAST

If you go with piston change using a "lighter" ring-pack AND go retro-roller, you should get very close to the 400 HP number. Minimal work on the heads would help, or a head change, iron's are fine but I would shoot for 9.5/9.75 for the C.R. This will handle pump-gas fine also.

If you do a piston change I would take advantage of the "floating" wrist pins for sure, maybe with a budget aftermarket conn rod!

Thanks, Gary in N.Y.

P.S. From past testing we've seen 355+HP (close to 400# Torque) on the flat-tappet platform with the factory OEM L-82 cam, Ross pistons (1/16" ring pack), and 9.8:1 C.R. The hyd-roller would add another 30 HP easily. We do this setup on most 100% stock-appearing units. Full roller, lifters and rockers. All the power in by 5800.

96 lt-4

Hyd roller cam is money well spent.Better heads = actually achieving your goals.Headers a must with oem heads and will certainly help aftermarket heads.
Keeping up with newer cars is a tall order these days.

AboveTheLogic

Roller cam if at all possible. I went with a XR276HR cam and blue print heads and it is pretty darn fast.

377

What's a good head to run? Are the L-82 heads any good for my app? My73 is a L-82 I could use them but I don't think they will make enough power. maybe 180cc intake or bigger?

jb78L-82

I used AFR 180's on my 78 L-82 with retro-Roller cam and 10.2:1 compression and the motor makes great power. Howards roller cam (lift .525/.525, duration 219/225, LSA 110 Operating range of cam 1,500-5,600 RPM....good bottom end, great mid range torque, pulls hard to 5,800 RPM...No comparison of the 882 L-82 cast iron heads and the AFR's but they are pricey...speed costs money though...

96 lt-4

Vortec heads would be an improvement over 882 heads.Any decent 180cc aftermarket head would be a HUGE improvement.Used ones pop up on ebay all the time.

377

i will look for better heads and go with a roller cam .thanks

biackbenz

Your L82 heads are probably 462624. My research has shown that these heads are cracks waiting to happen. I just had mine to the machine shop. One head is cracked near the water jacket and no longer repairable. I would have considered repairing them for the originality. Lots of them out there sitting on a shelf but if they are not cracked, they soon will be.

FWIW im looking into vortec or afr heads.

Good luck and have fun with it.

cv67

x3 on good heads and a roller cam no way youre going to make 400 hp esp by 6000 with what you have. You may still need to spin it a little higher to get there. Wouldnt worry about your power # get the best head you can afford your goal will come easier, cam it with your rear gear oughta run pretty good.

AboveTheLogic

FWIW, and to expand on what I mentioned earlier, I went with Blue Print's H8002K heads and when I contacted them about achieving 400hp, they recommended the XR282HR roller cam from comp. I ended up choosing the XR276HR cam for more torque and have not regretted that decision at all yet, my 355 has plenty of torque. In 5th gear at 65 I'm just under 2,000rpm and can part throttle bring the car easily up to 80mph for passing cars without downshifting. My cam is pretty much done by 6,000rpm which I feel is a nice safe number, although I've had my balanced and forged bottom end up past 7,000rpm without it exploding.

Heads:
http://www.blueprintengines.com/inde...cylinder-heads

Cam that BP recommended:
http://www.compcams.com/Technical/Dy...2HR-10_001.asp

Cam I went with:
http://www.compcams.com/Technical/Dy...6HR-10_001.asp

More specs in my sig below.

jb78L-82

I think you chose the right cam for a street application where torque is king............

dochorsepower

Agree! Definitely research modern technology heads. The 882 castings, L-82 or standard are good candidates for a boat anchor. Definitely go for a hydraulic roller.

377

thanks for the info going to call blue print pick their brain

AboveTheLogic

If you're doing a roller cam conversion on a flat tappet block, there are a few extras to consider. If you're going to go that route, you have some reading to do and a decision to make about whether or not it is worth it:

http://www.superchevy.com/how-to/148...ic-roller-cam/

GOSFAST

Just recently on the early SB platform we devised a method to eliminate the need for cam buttons and chasing any cam end play on the roller platforms.

Simple machining on the cam thrust surface, done during all the other machining, pick a stepped-nose cam (later SB's) and bolt it together. The thrust plate dictates the clearance. We now do this on all the 100% stock-appearing/full-roller SB's built. We also do the MkIV BB's the same way, set them up for the MkVI cams. No more cam-buttons here for the most part!

Thanks, Gary in N.Y.

P.S. This add'l machining will only work on an empty block while it's being built for now, but we may be able to change this method later and do it on assemblies where the t/cover is off and having a cam change. It is what it is for now!

AboveTheLogic

Very cool!

bluedawg

Check out afr and dart for heads.