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I have a 1968 350 short block. I want to put vortec or edelbrock e-tec aluminum heads on it.
What am i going to need besides the heads and intake? More specifically, summit offers a kit - NAL-GMP3287-1 - that converts an LT-1 (92-95) to an LT-4.
I want a roller cam when all said an done, and know i need to add or do something to the block for this to work. Any specifics would be greatly appreciated.
thanks!
chris
Hey Chris;
I am in the midst of building a sbc with the e-tech heads as we speak. I am using a 89 block which has the one piece rear main seal. However you can use those heads on the two piece rear seal blocks as well, without any problems.
If you want to install the E-tech heads, which are the ones I would recommend along with the intake Edelbrock recommends, they will bolt right in. If you want to use a hydraulic roller cam on the 1968 block, you will need to buy Comp Cam’s roller cam for the earlier style block and the 850-16 roller lifters or if you decide to go with a solid roller cam, you will need their solid roller lifters #818-16 or 888-16. Along with that, the recommended push rods and a true roller timing set for the earlier block, and you are off to the races.
From what i can tell, the heads do not come with rocker arms, and i am still uncertain of what lift cam i can go with. Did you get the complete heads with springs?
what rocker arms are you using?
what lift cam does edelbock say can be used?
i have read that no more htan .470 lift, but then i see specs that show a .525(at the valve) lift with 1.6 rocker arms...which with my math means a cam lift of only .328.
chris
Hi Chris
Edelbrock suggests using 1.5 rockers which you need to purchase separately and I bought Comp Cam rockers. I called Edelbrock and checked if I could go with 1.6 rockers, but they didn’t recommend it due to the fact that the springs were .009 shy of what is ideal clearance from coil bind. I could go with 1.6, but I would have to change the springs. Well these heads have huge flow numbers even at .500 lift so I really don’t need 1.6 rockers.
I got the ‘complete heads’ part #60989 e-tec 200 which come with springs and 64 cc chamber heads.
Edelbrock suggests using their roller cam part number 2201 for the earlier style block and obviously I am using part # 2204 for the later style block. With 1.5 rockers they boast 234/238 @.050 and .539/.548 lift and have 112 degrees of lobe separation with 5 degrees advance built into them.
Edelbrock did a dyno test with one of their crate 355 ci engine with only 9.5:1 compression with the e-tec 170 heads along with the combo above and a 800 cfm carb and it put out 435 hp and 435 ft/lbs. The e-tec 170 heads come with 1.94/1.55 valves and flow 232/183 @ .500 lift.
What I am doing for a customer is, I am using the e-tec 200 heads which come with 2.02/1.60 valves and flow 252/196 @ .500 lift. Besides that we are building it as a 383 stroker which will have 11:1 compression. These heads are capable of an additional 40 hp over the e-tec 170s plus the added compression should give us a further 25-30 ponies, not to mention the 10% added cubes. We are hoping for a healthy 500 on both numbers.
God luck. Oh, one note, if you decide to build a 383 stroker, when you set your timing, do not exceed 34 degrees.
If you have plenty of money to spend on the project I would go with the e-tec,but you have to consider that they only put out about 12 more HP than the vrotec. To some people $500 is worth 12Hp, but not me. If you use the vortec heads you will need groved self aligned rockers, wich come stock on the heads and can be found at any salvage yard and some center bold valve covers. You probably already know all of this, but I am throwing it out there just in case you didn't.
Considered the cheaper vortec heads, but the e-tec are aluminum so i can get more compression and within the budget. The short block has been broken in , but was only $300 and came with 'camelhump' heads, but without hardened seats, no intake, flywheel, dampener or water pump. Or bolts for these items...the details are always the killers!
What thickness head gaskets for a 9.5 or 10:1 with flat top pistons?
It is to go into an 84 camaro that currently has a 305 in it. I plan to re-use the alt/ac/ps and go with an elec fan. It already has a TCI 700R4 with 1800rpm stall converter.
Would prefer roller cam, but flat tappet would be fine too. Not decided on which one yet. For an intake, Edelbrock has their air gap model, and either a road demon 625 or 725.
Need headers and would prefer a true dual exhaust. emmissions compliance is not an issue.
thanks all
chris