Jartanyon

After months of researching and everyone's awesome help on here, I am just about ready to start ordering parts for my rebuild. Currently, I have stock L48 with 2.5" dual exhaust and 3.08 rear end. To it, I will be adding:

Flo-Tek (Speedway) 101505 Aluminum Heads
Summit G6920B 1.6 Aluminum Roller Rockers
Fel-Pro 1034 or 1010 Head Gaskets (per manufacturer recommendation - seems big, though)
Summit 226008 Dual Plane Intake
Summit G2410 Intake Gasket
Fel-Pro BS118291 Rear Main (while I am at it )
Jegs Block Hugger Headers

As far as the cam, I am torn between two kits:
http://www.summitracing.com/parts/cca-k12-206-2
http://www.summitracing.com/parts/cca-k12-234-2

I will also be changing out the trans pan/gasket, oil pan/gasket, fuel pump, water pump and timing cover/gasket.

Any final thought? Did I miss anything? Final thoughts on cam choice?

lvmyvt76

not doing anything to the short block(pistons, rings, bearings etc?)

Jartanyon

Good question! The plan is to open up the block first before I buy the upgrades - I want to see what I am working with as far as the pistons and rings go. If they are in bad shape, I will find out what it will run to bore and hot tank the block. I already have an idea on the cost of flat pistons, rings, etc. If things are really bad and the work will cost more than $1500, one of the options is to pick up a new GM base 195hp 4 bolt and add the mods to that.

cagotzmann

What does the parts list $$ come out to. My 1978 L48 needs an update also. I have been looking at ZZ5 crates to start over. But @ $6600 for me in Canada, I am not sure it's the best for the $$. My L48 with 177k KM (110k Miles) might need to much work and with 2 bolt mains, not sure I want to start there.

Jartanyon

Comes out to about $1300 including a new fuel pump and some other things to freshen up. Take out the rocker arms and drop another $200 from the price. Add in the 4 bolt GM base engine and you are at a very reasonable price for a 4 bolt rebuild with performance upgrades. Dished pistons would be a weak point, though.

haydenray

Just hhad my L48 rebuilt with a roller hydraulic setup and Dart heads. The engine builder told me he has taken 2 bolt blocks up to 600 HP without problems, not to worry about at 400 . Just passing this on. What I have read is that while the 4 bolt is marginally better for strength. The 2 bolt is good enough.

I quizzed several of the crate builders and was disap1oined to find out how many of them put used "inspected" parts in their product. Something to check on.

Ray

63mako

Talk to Chris Straub (Strubtech) here on the forum. He has a head that flows better, already set up with the correct springs for whatever cam you choose for similar money. I would go with a 1094 gasket and a comp XE262H cam and lifter set.
http://www.summitracing.com/parts/cc...38-2/overview/
Then add new timing set.
These are a better price on rockers and good quality.
http://www.summitracing.com/parts/cc...make/chevrolet
Before you tear it down do a compression and leakdown test to see where your shortblock is. How many miles?

Jartanyon

Thanks haydenray - sounds like the stock two bolt should be ok.

@ Mako - thanks. I will shoot Chris a pm. I originally had that cam, but changed to a lower power band and lower lift. Will that lift be ok with the heads? I know the Dart and a few others were not. The engine has about 65,000 miles on it...

63mako

Heads will like the lift and duration. Better cylinder filling and good match for your compression and combination. The XE has gotten a bad rap for wiping lobes but the 262 I have never heard of this issue as long as you check everything, use the right springs, check for binding at the pushrod, use plenty of assembly lube, and break it in right with the right break in oil, change to a conventional High ZDDP oil after break in and run a High ZDDP oil preferably a good synthetic after 1000 miles. Ask Chris for a cam recommendation to match his heads and your combo and needs, that is what he does. He my contradict my advice and I am good with that. I would always recommend a Retro-Roller upgrade if at all possible.

BKbroiler

Don't worry about the 2 bolt mains. I have close to 200 quarter mile runs and 8000 street miles on my original L48 block, now a 383 running 12.1s, with no problems.
I used the Comp xe262 cam and I would recommend that too.
BTW, with the 3.08 rear, you should really think about a higher stall speed converter. Maybe around 2500 rpm.

Jartanyon

Just out of curiosity, why the XE262 and not the XE256? If the goal is to keep as much low end torque as possible, wont the 300 rpm's make a difference? Also, will the lower power band be better with the stock torque converter?

63mako

The goal is not to keep as much low end torque as possible. The goal is to optimize your combination of components to produce the best results for your application. Every part selection is a compromise in one form or another. 256 Operating range is lower but the duration and lift will not maximize the power potential of your aftermarket heads. It becomes a restriction of airflow through the engine. You do not want to go too big on a cam but to small is not a good option either. The 268 is largest with the stock convertor. The 262 matches your new compression ratio and will be fine with the stock convertor but a higher than stock stall convertor will run faster 1/4 mile with a 3.08 gear. That is another compromise as a higher stall convertor is less efficient and generates more heat. Make sure you do a performance recurve of your distributor and use a vacuum advance can that matches the cam.

Jartanyon

Sorry for the confusion - in my original pm, I had stated I wanted as much low end as possible with the new cam and the XE256 would be a better option for that. However, I completely understand matching for the best optimized outcome with the new heads.

As far as re-curving, will the cam come with those specs?

cagotzmann

As for crate builders (Chevrolet performance GM Crate motors) from the order catalog they have a tag at the bottom in fine print

"Chevrolet Performance does not utilize any used or remanufactured parts in this crate engine , expect for the starter, alternator and power steering pump" this is for the new ZZ5 350 turn key 19301294. Which crate builders did you querry ?

StraubTech

PM answered.

Jartanyon

Thanks Chris - I look forward to hearing from you.

As far as the original Flo-tech heads listed above, I noticed that the springs are rated for up to .550" lift...does that mean I wouldn't need the replacement springs that come with the cam kit also listed above?

iokepakai

Refreshed my 76 80K miles L48.Aluminum heads,1094 head gasket,Air Gap intake,Summit carb and a retro hyd roller cam.Motor had good comp before top end and cam change.Retro roller cam is the way to go if you have the funds.The roller is well worth the cost.The ol L48 is like a new motor..The power just builds right off idle.Cam in the motor is a Crane Cams 119821....This was supposed to be a tempo refresh till I had the funds for a Dart SHP 400ci.Since she running so sweet I'm gonna run her till it blows up!

scottyp99

Well, yes, it does mean that. You won't have to change the springs. However, since it is a flat tappet cam, it might be a good idea to switch them anyway. The speedway head's springs may be more than you need, and with a flat tappet cam, you want to run the least amount of spring pressure you can get away with, to lessen the chance of wiping a cam lobe. See if you can get the spring specs and compare them, if they are very close, you could probably get away with using the speedway springs. Look for installed height, and spring diameter, too, the speedway heads come with pretty wide springs, which require special rockers. The Comp springs may be narrower giving you more rocker arm options. There are a lot of variables here.

Edit: Also, be advised that the heads you have listed are angle plug heads. Here is a link to the same heads with straight plugs.

http://www.speedwaymotors.com/Flo-Te...lug,25118.html

In the Q&A section, Speedway recommends the Comp Cams HE268H to go with these heads. The XE262H has a very similar power range, so it should work well, if you take Speedway's word for it. Good luck!!

One thing about these heads is that they have an excellent intake/exhaust ratio, (don't get too exited, I have a feeling it's more due to a poor intake than an excellent exhaust port) which might make you lean toward a straight grind cam.

Scott

63mako

I probably was unclear in my response. The 256 has a lower powerband. With that comes lower duration and lift numbers. It will likely be a little stronger off idle. That small advantage will be gone before you hit 2000 RPM. The lower midrange to redline will likely be 20-30 foot pounds more (maybe more)across the board with the 262 due to better cylinder filling due to the valves being open a little longer and a little wider allowing the better heads to flow.
Recurving the distributor is best done following the papers that Lars has posted. Contact @ V8FastCars@msn.com. You will also want to match your new vacuum reading with a different vacuum can that Lars also has a paper on. Total cost will be about $25 and the upgrade in throttle response and lower midrange will be dramatic. Shoot him an Email.

buckhorn 76

if you're going with a complete rebuild it makes sense to go with a roller. my 406 is getting the howard's 113215-10 along with afr 195's and 1.5 roller rockers. why worry anymore about zddp.