Lue

Hi Everyone,


I need some help rebuilding my 79 350. I am going to be dropping the engine in a daily driver/ commuter, so I need it to be reliable!!!! To give you guys an overview of where the car came from and where it’s going. The engine (350) and tranny (TH 400) came out of 79 regency (98), and both are going in to a 1978 G-body car. To gives you guys a hint, the lightest G-body GM made….
So I have the engine on a stand, and stripped down (heads, manifold, oil pan, Etc) are off. I’m ready to order a cam kit but I don’t know what kind of duration and lift should I get. Comp cams, has an Xtreme Energy cam and lifter kit that I seen, the specs and items that are included as follows

Cam Style:
Hydraulic flat tappet
Basic Operating RPM Range:
1,600-5,800
Intake Duration at 050 inch Lift:
224
Exhaust Duration at 050 inch Lift:
230
Duration at 050 inch Lift:
224 int./230 exh.
Advertised Intake Duration:
268
Advertised Exhaust Duration:
280
Advertised Duration:
268 int./280 exh.
Intake Valve Lift with Factory Rocker Arm Ratio:
0.485 in.
Exhaust Valve Lift with Factory Rocker Arm Ratio:
0.490 in.
Valve Lift with Factory Rocker Arm Ratio:
0.485 int./0.490 exh. lift
Lobe Separation (degrees):
110
Intake Valve Lash:
0.000 in.
Exhaust Valve Lash:
0.000 in.
Grind Number:
OL XE268H-10
Computer Controlled Compatible:
No
Lifters Included:
Yes
Lifter Style:
Hydraulic flat tappet
Valve Springs Included:
Yes
Outside Diameter of Outer Spring (in):
1.494 in.
Retainers Included:
Yes
Locks Included:
Yes
Valve Stem Seals Included:
Yes
Timing Chain and Gears Included:
Yes
Timing Chain Style:
Double non-roller


Will the factory Crankshaft be ok to use, or do I have to get a bigger one and bore the engine? I also read this about getting a Hydraulic flat tappet cam, on www.442.com.

A hydraulic flat tappet cam's lobes are ground with a slight taper which spins the lifter and pushes the cam rearward. Also consider the rearward thrust of the cam produced by driving the distributor gear, which also drives the oil pump. The back of the cam gear then contacts the block preventing the whole assembly from going any further back. OTOH a roller cam has perfectly straight lobes. Of course to keep the cam from wandering around you must use a thrust plate or cam button.

Oldsguy

Welcome to our site. I know many people use comp cam products and like them very much. That last paragraph is really just describing the difference between hydraulic and roller cams concerning the function of the lobes in reference to rotating the lifters. Roller cams are made to push roller style lifters so they don't need to be rotated. Just a difference in design, you don't need to change to a roller cam set up in my opinion. In determining if you need to do any maintenance to the block you shouldn't have to consider the change in the camshaft you are going to use. More importantly, the condition of the crankshaft itself and the bore of the block would come into play and your machinist would be able to recommend that. Don't confuse the term bore (as applied to the crankshaft) with bore (as commonly referred to cylinder size and "boring them out .030 or .060"). They are two different things. The former, I already mentioned, the later applies to the condition of the cylinder walls themselves. You may or may not need that done as well although I don't bore the cylinders unless they need it. Some people do it to "hop-up" the engine but I don't think that is necessary.

Olds64

If you are going to put an aftermarket cam in your rebuilt engine you also need to consider if it will work well with the stock intake or if you need to buy an aftermarket intake. You also need to consider a carburetor choice as well. I know Edelbrock makes the kits where you can buy a carb, cam, and intake all togethere; however, I have never heard if these are any good.

Like Oldsguy said, you don't need a roller lifter cam. That would be too radical for a daily driver. If you want a mild rebuild then I would consider a little bit of cam and maybe an aftermarket carb. I like Edelbrocks myself. However, I really like the Quadrajet and I have heard that you can get them really reasonable rebuilt professionally. I know Oldsguy just had this done.

WELCOME!

88Deltakid

How much horse power will that be for that engine? I have a 1978 Oldsmobile with a Olds V8 350 but it will not be my daily driver.

captjim

Are you replacing the pistons or re-using stock? Stock compression ratio on that engine is around 8 to 1, making that cam WAAAAAAAAAAAAAAAAAY too big. Easiest upgrade is early 350 heads which flow better and will bump Cr up into the 8.6 to 1 neighborhood. Then, get a cam in the 210 @ .050 range.