Thread: Need some help my friends...

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Small Block gave me an engine for my '48, a early '80's model 4 bolt 350 that has been punched out 40 over. Everything is there but the crank. First question: will any crank work and whats the best for it.
Next, it came with a set of injector heads I think, they have 1.94 or so intake valves but they have those four bolts down the center of the valve covers. The quadra-pig manifold that came with it was also machined in the two center bolt holes on each side to make them bigger. Question #2: Why?
Question #3: Are these heads going to work, they have marks like this: " //" on the ends of them. I like the big valves but not the valve covers. what are they?

Any help would be appreciated

Dear Brickman,

I am new to SBC350 technology also but I found a web page to identify the heads at:

http://www.angelfire.com/tx5/randysr...Headguide.html

The cast no.s are in the middle of the head between the rocker studs and the numbers in the web page refer to only the last three digits.

Best Wishes,
Don Shillady

brick,
#1-sounds like a great candidate to put a 383 stroker assembly in. Check the PAW catalog. http://www.pawinc.com/

#2-sounds like they might be Vortec heads. The holes you described were modified because the bolts go in at a more vertical angle.

#3-from '86 on the SBC's had the "center bolt" covers. There are lots of aftermarket, and a couple factory covers that look better. However, they do clamp better for sealing than the older style. But, if you really dislike them, adaptor plates are available to allow the use of the older style covers, they run about $100.

Brickman, if the valve covers are all you dislike, check either Summit or Jegs, I know one of these companies has a kit that will allow you to switch to the old style valve covers...just a little info.
See ya,
Montemanchuck

Welcome back Tech, glad to hear from you again, and also welcome to my good friend Montemanchuck, glad to see you here.

I don't mind the valve covers at all but I am a little concerned about what I have read about Hi swirl and not recomended for Hi-pro applications.

Don, that is an excellant referance page, thanks. Told me that I have '80's model Vortec heads alright.

Deffinently been thinking stroker Bob, the block is in perfect condition, just needs a little machining on the bottom of the cylinders for clearance which I can do myself.

Do you guys think these heads will be worth me porting and polishing?

Richard/Techinspector1,

Allow me to learn from you regarding "squish". The message above has three points of interest to me. First, I am learning that you recommend the space between the top of a piston at TDC and the underside of the head (SBC or wedge head; not hemi-head) be minimal to permit use of higher compreshion ratios without detonation. This is a new idea to me and I want to understand it. There may be a safety problem in that as an engine wears there may be wear in the piston pin and rod bearings that will allow the piston to go higher as it passes TDC and gets dragged down due to the inertia of the piston mass. This could lead to a catastophic collision between the piston and the head if contact occurs. In another thread you recommended 0.035" as this space formed from a deck height of 0.007" and a thin gasket compressed to 0.028", summing to 0.035". Thank you for the Chevy part No. for the thin gasket (10105117). I am not clear on what the standard deck height is with "stock" or "stock replacement" pistons but one shop told me it should be 0.025" I am trying to use your method with combinations of more common parts and avoid the cost of decking the block. Thus if the deck height is 0.025" with stock replacement pistons and I use a Felpro gasket which compresses to 0.015" the "squish" should be 0.040" which should be a cheap way to approximate your recommendation. The additional question is whether eybrow valve reliefs or a shallow dish in the top of the piston spoil this "squish" ????? For a short duration cam, I like the dual pattern Comp Cam XE250, but maybe the Lazer 255 or Isky 256 "square" cams would work with high compression to start a new trend in street rod engines using short duration cams and high compression to increase the MILEAGE of SBC and other engines in times of expensive fuels.
Second quick question: is the manifold match to vortec heads more difficult to achieve than with earlier heads?
Third question: Does not installing a 383 stroker crank involve shaving/grinding the outside rod bolt (potentially weakening it) as well as grinding clearence on the inside of the block? To my mind it is serious to mess with already weak rod bolts on a first time basis at home and I would be more comfortable with a 383 block set up by a shop who has done it before. Am I wrong about the rod bolt clearance? If this is easy to do in a home garage on a one time basis I would like to know about it. Maybe there is enough wall thickness in the skirt of the block to avoid any weakening of the rod bolt?
Tell me anything more that you can about why reduced squish works and is the 0.040" small enough and what dish or eybrow volume does to the squish.

Just tryin' to learn,
Don Shillady

Don, I have recently seen a 350 block preped by a shop for a stroker crank and all they did was grind half moon grooves out of the bottom of the sleeves. I don't know about the rods, they came with the stroker kit. The rod bolts looked normal to me.

Now it's been a while but I remember some people used to shave heads and blocks to gain compression to run in stock classes. I don't know if this is useable with high-pro cams, probly not. I too wonder how big of a cam can you use with a 10 to 1 compression piston without bending valve's on piston tops.

Now I have a question for you Don, how are your studys for smaller cam, higher compression for better mileage panning out? Do you think it's workable? I am interested, I may try it.

Also Tech, do you think that if I do the stroker crank w/vortec's I would gain anything using massive carberation? I have a love for dual-Quad tunnel rams. I know they are not street manifolds but I love BOLD motors? Just a thought.

Brickman,

Thanks for your interest. To be honest I have only second hand verbal information from a shop guy who did a 383 stroker whereas you have seen it so I yield to your statement of ease for the process. I have only rebuilt a MG Midget 1250 cc 4cyl, a 1300/1600 cc VW engine twice and a Pinto 2000 cc OHC in the past (with dabblings on 59-AB flatheads long ago) so the SBC350 is new to me. There are newer 383 kits that may have this all figured out compared to some original tests adapting 400 cranks. I have read several articles on stroking a 350 but I still would like to be sure the rod bolts rotate in the clear and are replaced by stronger bolts. Just for my own interest I would like to know if the 400 harmonic balancer is used, but I have decided to stay with a 350 rather than a 383. Back to more mpg. So far the only person who has agreed with me is Richard/Tech1 and he wants to flirt with very close tolerances between the top of the piston and the bottom of the head. Economicaly, I can't experiment much or waste an engine just for fun so I am having second thoughts. My present thinking is to just wimp out and buy a crate engine from Engine Manufacturers in Charlotte. They have a low end crate engine that comes with a Performer intake and for $50 more you can get the MTC-1 cam from Melling which seems to be a very close approximation to the Edelbrock Performer-plus cam. Thus with only added headers one can get about 280 HP in close approximation to the Edelbrock Performer package. The interesting thing about this engine is that by figuring back and assuming their deck height is 0.025", their 9.1:1 C.R. must be achieved with a Felpro 0.015" head gasket. This is close to what Techinspector1 wants (he wants 0.035" squish) in that the 0.025" and the 0.015" yields 0.040" squish and a 9.1 C.R. Alas that engine uses the smaller valves with 76 cc chambers and the C.R. is a lot lower than Tech1 expects. At this point I could envision changing the cam to the XE250 and in part achieve the short-cam-high-compression model. For me that is the safer thing to do in that if the experiment fails I can still run on 92 or maybe even 89 octane gas and the extra 0.005" in the squish makes me feel safer that I will not smash a piston. I will still have the 461 double-hump heads and maybe later I can go for 10:1 or more. In case anyone wants to try it here are the two setups:

1. The Risky Experiment

a. 461 SBC 58 cc heads with flat top pistons (7 cc for eyebrows) to yield well over 10:1 C.R.

b. Comp Cams XE-250 short duration cam (I=250, X=260)

c. Thin head gasket to keep squish small (0.035"), block decked to only 0.007" with Chevy part no. 10105117, 0.028" compressed as suggested by Techinspector1 (total squish =0.035").

d. extra care in smoothing out cylinder walls and other potential hot spots to hopefully eliminate detonation. Tech1 suggests zero-gap rings but you would have to leave some gap for thermal expansion.

TechInspector1 hopes for up to 25 mpg!!!!!!!!

2. The Safe Experiment

a. 883 smog heads with 76 cc chamber (Dart heads as in the Comp Cams test would obviously be better); anticipate C.R. is only about 9.1:1, ie closer to the value used in the Comp Cam 250 test which was 9.25:1.

b. Comp Cams XE-250 short duration cam

c. Felpro head gasket (0.015" compressed) with 0.025" deck height to give a safer 0.040" total squish.

d. smooth the cylinder walls with a fine hone to try to remove hot spot detonation.

My "safe" economic thinking is that if I go with the 9.1 CR crate motor and the Comp Cam-XE250, I could at some future point buy the Dart Heads and then be more sure of reaching the results of the test shown in:

http://www.compcams.com/Technical/Dy...50H-10_001.asp

Well you did ask! Another potential problem is that the XE-250 is a pretty violent cam so pinning or threading the rocker studs would seem to be necessary. Anyway Techinspector1 agrees that a short duration cam should lead to better mileage and the XE-250 test shows that low rpm torque is very good without sacrificing much high rpm power, that is contrary to most knee-jerk thinking and maybe Comp Cams will sell a lot of these cams as gas gets even more expensive. The idea that you can still use very high compression (the real secret to power) with a short duration cam by using this tight squish is certainly not safe for worn engines IMHO, but I would like to study this more before reducing the squish to 0.035" or raising the CR to 11:1, BUT I am still pondering this. All of this assumes a tall rear gear and that is also backward thinking, BUT again what are the alternatives? By the way our cheapest regular here in suburban VA is now $189.9/gal with high test at $209.9, maybe "we" need to scratch our heads a bit and come up with something new! I would certainly welcome a more complete essay on this problem from TechInspector1 at his liesure. As I said in another thread my "Golden parachute" at retirement is really a "Copper parachute" and I want to end up with something that runs well and if all I get is 18 mpg on the Interstate that will have to be what it is, but 22 mpg would really be a breakthrough if the engine can still produce over 300 HP on occasion! I am new to this forum but I greatly appreciate the collected expertise available here. I will ponder this more but for now I have to sort out the TCI 4-bar rear kit I got today for my 8" 2.79 rear. Maybe TechInspector1 could figure out how "we" could do this with standard parts like the commercially available XE-250?

Best Wishes,
Don Shillady

Thanks Don, those are two very interesting ways to go. I myself am wanting a high compresion engine just because I love the throttle response they give. I have good size valves in the injector heads I have but I am not sure what size the chamber is. I am going to find out some how and biuld accordingly. I have already started taking them down and the porting and polishing will begin tomorrow or monday. I am interested in putting screw in studs in them but not sure of the cast. If I'm going to use roller rockers I had better I think.
Is the XE250 Comp Cam a hyd. lifter cam or a roller cam? I am wanting a roller cam for longer life and quicker rpm gain unless I am way in left field. Please feel free guys to jump in and tell me I'm an Idiot at any time!
I'm looking for the 400 hp range but have no idea yet what that is going to take.

What is the average HP of a 383 stroker motor?

I see that there are several companys that make Stroker kits and the PAW kit seems the cheapest. Is there anybody that has used the PAW kit and how they liked it?