Thread: 327 sj for a 78 nova

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Hello club hot rod. I have a 327 going into a 78 nova that ounce housed an ac 250. now I would love to keep the ac but my main thing is having a fast, fun car to street with. the 327 has been bored over .030 now I need help on the build I have a set of power pistons 2044p but think the wiseco forged k398x3 would be the piston of choice. with promax performance 2151 heads
arp rod bolts
trick flow push rods
victor junior intake
holley 750 double pumper
all pushed by a lunati solid tappet cam 401c3lun. seems like a good rig with the compression ration somewhere around 11.5:1
it will be backed by a th400 tranny and a 3500 stall if necessary. does this set up sound good to yall. also this engine will eventually be hit with nos just something to keep in mind. thanks in advance
nic

If your doing a build with that many non stock items-------unless your looking for a numbers matching(doesn't sound like it) you should look at possibly building a stroker 383 or 406 from a 350 or 400 block---even a Dart SHP with the bigger bore and put some cubes in it so you have power-------------

I like the 327. 350's are too common and now 383's are taking their places. Everybody does a similar build so I like when someone switches it up a bit like a 327, 388, 406, or 408.

You have a good point but it seems everybody is doing the same thing

well since I have the engine lying around and an empty nova along with a th350 and a powerglide and a 305. The most logical choice is build the 327 for the nova and create some garage space for a future 350 or 383 build. I think my combination should pull around 300 - 350 horses or so. enough for me to get around town. Thanks for the replies. I just need to know if the build is logical or is something needs to be changed. also can I run a/c with the promax performer 2151 heads.

Welcome to CHR Nic.

You said that you’d like to have a, “…fast, fun car to street”. What you’ve suggested will be neither. I love the 327 and have nothing but great memories of them built in various combinations. You have way too much cam, the Victor Jr is too much manifold, and a 750 is too much carburetor for this engine and with stock crank and rods, nitrous is a recipe for broken parts.

Was your block decked when bored? I’m curious how you came up with 11.5:1 on your CR – with the heads having 64cc combustion chamber volume, Wiseco pistons (+3.20 piston head volume) in a 4.030 bore and stock stroke you’d need a zero deck height and a head gasket less than .020 – all of which would lead to some very tight and specific tolerances in the valve train – easy for a race mechanic that adjusts as necessary between runs but tough with a solid lifter cam on the street.

If you really want a fun to drive car it needs to be dependable and start with a touch of the key. Unless you’re looking to race your Nova it may be smart to tame this build down a bit. Stay with the Vortec heads but use some good cast pistons and work for a 9.5:1 compression ratio. Use a hydraulic cam with less lift and duration in the 220 range and top with a Performer RPM and a Q-Jet or 650 Edelbrock 1406 carburetor. Some ceramic coated hookers and 40 series Flowmasters with your TH400 and a stock converter will be a lot more fun and a lot less embarrassment.

Give us a bit more information and there are many here who can help you decide what’s best for your application. Ask Techinspector nicely and he’s a wealth of information on specific builds.

Regards,
Glenn

ok Im not sure how to tell if the block has been zero decked or not. I bought the rebuilt engine the edelbrock intake and carb plus a huge crane energizer 284h12 and stock 75cc heads. The motor had only ran once before I bought it and the powerglide for $400.
so the cam is to big how about the comp cams 268xe.

I have a edelbrock performer 2101 intake as well a edelbrock 1406 650 carb, so do I still need the performer rpm intake? also this motor may get backed by a 700r. do I need to change pistons from the sealed power 2044p pistons (I think they have a 5.4cc dish).

so the motor has only run once since rebuilt????

yup it was mostly due to incorrect part selection. As soon as I got it I broke it down. heads looked good. one bent pushrod. block is fine as is the pistons and the cam. now I'm rebuilding it, better cam, better heads, better cr.

OK, first things first.....
A production 327 block will have a block deck height of ~9.025 (blueprint measurement).
Your task is to find a "stack" of parts that will fit into this space, then cut the block decks to establish your piston deck height. The crankshaft radius is 1.625", the rod length is 5.700" (blueprint measurement) and your TRW 2044P pistons have a compression height of 1.668". Add these values together and you will find a stack of 8.993". If the block were actually 9.025" (highly unlikely), the piston deck height would be 0.032". Deduct 8.993" from 9.025" and find 0.032". So, the piston would be down in the bore by 0.032" with the piston at top dead center.

At this point, you know nothing about the block, so haul it down to the machine shop and have them measure the main bearing bores for being round and parallel with each other. If the bores are valid, great. If not, have the shop hone or bore the mains to bring them into spec. The main bearing bores are the cornerstone of the motor and if they're not valid, nothing else will be valid. Now, with the mains trued up, have the shop measure the block deck height. on all four corners of the block. This will tell you how much stack you can use and how much needs to be trimmed off the block decks to reduce the block deck height so that your intended stack will fit into the block and also to set the piston deck height so that you can choose the proper gasket thickness to set your squish, the clearance from the crown of the piston to the underside of the cylinder head with the head gasket in place and the piston at top dead center. Current thinking sets the squish on a street-driven small block Chevy at 0.035" to 0.045"

The Wiseco piston you mentioned is a stroker piston. The compression height is 1.304", so it would be nearly 3/8" down in the bore with the piston at top dead center. That's why I'm trying to teach you about the stack. Math does not lie. It is black or white, no gray areas.

Now, we have had the machine shop to cut the block decks to a block deck height of 9.005" because our stack is 8.993" and we want a piston deck height of 0.012" so we can run a GM 10105117 head gasket (0.028" compressed thickness) and set the squish at 0.040". (Add the [B][piston deck height/B] of 0.012" to the 0.028" gasket thickness and you find 0.040" squish.

OK, there's the short block, ready to go except for blueprinting the oil pickup to the bottom of the oil pan (3/8" clearance).

Now, as far as heads, current thinking puts a limit of around 9.5:1 static compression ratio for use with iron heads and 10.5:1 with aluminum heads. Looks like you like the iron heads, so we need to cap the SCR at somewhere around 9.5:1 or a little more. The 2044P pistons have a ~5.5 cc crown, the combustion chambers are 64cc's, the head gaskets are 5.766 cc's, the cylinders are 679.33 cc's and the piston deck height is 2.5 cc's. Add all 5 values together, round off the number and come out with 757.1 cc's total. Now, deduct the cylinder cc's (679.3) from the total and find 77.8 cc's. Now, divide 757.1 by 77.8 and find a static compression ratio of 9.73:1

If you don't like the 2044P pistons, use these pistons.....
http://www.summitracing.com/parts/ue...-030/overview/
Their compression height is 0.007" taller than the Speed Pro units, so cut the block decks to a block deck height of 9.012" and use the 10105117 head gasket for a 0.040" squish.

Now, you need to match up a camshaft with the static compression ratio to find the proper dynamic compression ratio.
A cam with an intake valve closing point of 35 degrees after bottom dead center at 0.050" tappet lift will generate a dynamic compression ratio of 8.54:1 and will make good power on pump gas.

If you like a solid flat tappet cam, a Crane 110911, closing the intake at 36 degrees and making a DCR of 8.49:1 would be a very good fit, making power from 2400 to 6000. I love the sound of solid lifters myself and today's technology should allow twice-yearly valve adjustments. Use lifters with the oiling hole EDM'd into the crown of the lifter and order the camshaft nitrided. With any kind of flat tappet cam, it will be necessary to add an extreme pressure lubricant to the oil when you change it. These high pressure lubes have been removed from all the off-the-shelf oils. Do not trust anyone who says that such and such an oil still has these ZDDP additives in it. Put the ZDDP in your own off-the-shelf oil with each oil change and drive on.
http://www.summitracing.com/parts/cca-159/overview/

The cam will want a minimum 3.73 rear gear and a 10", 3500 stall converter. Yes, a 3500 stall converter works great on the street. Use a genuine 10", not a fosdick 12" unit with the fins bent over. You're gonna need an Auburn locker and some serious rubber on the rear.

Use an RPM intake manifold (not the air gap), topped by a 750 double pumper and 4" x 14" air filter assembly. Finish it off with 1 5/8" long-tube, tuned headers and an X or H pipe immediately after the collectors. Run the pipes out to the back of the car, through mufflers of your choice. Terminating the pipes under the car tags you as a Ricky Racer type who doesn't know any better.

Regulate fuel pressure to 5 psi max. The carb only needs enough pressure to keep the bowl(s) full, that's all. More pressure will not make more horsepower. What it will do is to unload the needle and seat in the bowl and allow the fuel pump to blow raw fuel into the intake manifold, creating a tuning nightmare for you.

Re-curve the ignition for 16 degrees lead at the crank and 18 degrees in the weights, all in by 2800. If the motor wants to buck back against the starter because of the crank lead, interrupt the power line to the coil and splice in a momentary switch (push to interrupt power), so I'm describing a normally closed switch. Push the button, crank the key switch and let go of both. The motor will be running, no muss, no fuss.

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thanks for the reply techinspector1 for the much needed knowledge. ill get down to the machine shop tomorrow and post the results funds permitting that is.

GM 10105117 this gasket has a 4.00" bore will it still fit a 4.030 cylinder, or does that matter?

Originally Posted by bluepyro

GM 10105117 this gasket has a 4.00" bore will it still fit a 4.030 cylinder, or does that matter?

GM says it will work fine in a +0.030" motor. That's according to the forum at Scoggin-Dickey Chevrolet.

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Thanks tech, you are full of usual information for a newbie like me.

also which rpm intake should I get for this combination
and which set of 1 5/8" long tube headers should I get? thanks for the help guys without youi would be running in circles and getting nowhere.

Originally Posted by bluepyro

Thanks tech, you are full of usual information for a newbie like me.

You don't know the half of it.

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