Next winter project rebuild a SBC - Impala Tech
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post #1 of 14 (permalink) Old 05-24-2011, 04:07 PM Thread Starter
Join Date: Jul 2010
Location: Pine Island, MN
Posts: 18
Next winter project rebuild a SBC

This winter was to get 72 Chevelle back together and running. My son who is 10 was an awsome helper he was asking what are we going to do next winter.
Last night we were talking about rebuilding an engine for the 67 Impala SS 327, TH400, 12 bolt non posi hwy gears.
The original engine was a 327 275HP with double hump heads we have it. I also have a mid 80's Chevy 350 that I pulled out of a pickup before we took it to the junk yard. The engine ran really well when pulled
We are going to do the work ourselves. Accept any machine work and heads.
Got to thinking.
1) Is it worth it to pay to have the double hump heads rebuilt ? Should I get some aftermarket heads ?
2) Should we take the 350 and rebuilt that instead of 327 ?
3) Rebuild the 350 ?
4) Should we make a 383 out of the 350 (this is my favorite as long is there in not a lot of machine work to block) ?
Looking for the most bang for my buck. The 383 would be nice build for low end torque to move the big Impala. Can get much better flowing heads these days that may be cheaper then rebuilding double humps.
Please share thoughts and experience.
What are good flowing reasonably priced heads ?
If possible would like to keep this original looking from the observer perspective.
There is a budget too : ( most bang for buck keep it very reasonable.
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post #2 of 14 (permalink) Old 05-24-2011, 05:35 PM
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Most bang for the buck is World Products Sportsman II heads (which you can find used to save even more as people opt for bigger aluminum heads later). They flow as well as the stock Chevy Vortec cast iron head does below 0.450 inch valve lift (which is really saying something) and they do not have any lift restrictions above that point, the way the Vortec head does. On top of a 355 or a 383 you will be ahead of the game over the older 327.

The 383 can be clearances at home with grinding stones and burs or you can buy H-beam rods which allow for more room for the crank to swing with less grinding for clearance.

Big Dave

Last edited by Big Dave; 05-25-2011 at 01:26 PM.
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post #3 of 14 (permalink) Old 05-25-2011, 10:51 AM
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What are your goals? Do you care about originality or somewhat original appearance? Care about the MPGs? Want it to be quiet or loud hot rod sounding?

You can make a 383 out of either engine, the 350 or the 327, but there is going to be a number of things to work out to be successful. Getting the right compression ratio and quench come to mind.

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post #4 of 14 (permalink) Old 06-03-2011, 03:14 PM Thread Starter
Join Date: Jul 2010
Location: Pine Island, MN
Posts: 18
Ran into another option found local a 350 Vortec block all machined and ready to build. Bored 30 over honed, decked to square, align honed, blasted cleaned, painted black (not orange : ( ). comes with resized rods and machined 350 crank. I may sell crank and rods. There was an engine manufacturer that closed its doors and they have blocks left over that were destined to be rebuilt. Afer talking to the machinest and getting estimates on machine costs on 327 or 350 the 350 vortec may looks to be a cheaper option.
There are some considerations with the 350 vortec block.
1) 1 peice rear seal +
2) All machined and already checked out +
3) Think I have to run electrice fuel pump -
4) All setup for roller lifters big savings here ++
5) different oil pan -
To answer the questions on build
- Get away with as much CR I can to run pump gas and yes MPG is a consideration as this will be drivin on trips on the Highway. I think a more torque engine with the taller gear, TH400 and highway cruising is what is needed.
-Somewhat original look would be nice not required, I have thr origianal engine wrapped up.
-always like it to be a little loud. It sounded ok to me when the 327 was in it and what looks like old cherry bombs. It sounds nothing like the 557BBC or 427BBC.
- Heads: I am looking now will consider the World Products Sportsman II or what ever has good mid flow numbers. Not expecting to put in a huge cam may even want to keep old ram horns exhaust, unless headers will free up a lot of power.

any thoughts on 383 build using 350 Vortec block. I really like the idea of having the roller setup being much more reasonable.
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post #5 of 14 (permalink) Old 06-03-2011, 08:12 PM
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You will need to buy a one piece 3.75 inch stroke crank as the original SBC 400 that used the 3.75 crank that makes a 383 in a 0.030 inch over bored 350 block was only made with the two piece rear main seal. I recommend an internally balanced crank when you buy it as the 350 is internally balanced and you can reuse the flexplate and damper off the 350.

I see no need to throw away the factory rods if they have already been rebuilt as they will work quite well with the right piston (one designed for a 5.70 inch rod). Just have your new pistons pressed onto the remanufactured rods.

Big Dave
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post #6 of 14 (permalink) Old 06-04-2011, 12:45 AM Thread Starter
Join Date: Jul 2010
Location: Pine Island, MN
Posts: 18
Any reccomendaitons on internal balanced cranks. All the internal ones are forged and are pretty spendy. Plus any upgrades needed on the connecting rods ? How much can the stock rod take and are they small enough where they need to be to minimize clearance ?
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post #7 of 14 (permalink) Old 06-04-2011, 07:15 PM
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Stock Chevy forged steel 5140 alloy is plenty strong enough to handle almost anything the block can hold. To upgrade the rods you would use a premium ARP rod bolt (which would require the rod to be resized again). It is the bolt not the rod that fails.

Believe it or not adding an ARP bolt to a steel Chevy rod is only a few bucks per rod cheaper than buying the same rod bolt wrapped in a new 4340 alloy chromemoly rod from over seas, as the machine work is the most expensive part; not the chunk of steel it is made from.

As to the crank consider the cost of a new balancer and fly wheel (which will be required, and is not an option) if you choose an externally balanced cast crank because it is a little cheaper.

An Eagle or SCAT internally balanced crank has two extra counter weights on the crank and it not only saves money but reduces stress on the nose of the crank and lengthens the rear main bearing's service life as there is less flexing on the ends do to a counter-weight being slung around.

I have not done a cost to benefit analysis in a while as I always opt for the internal balance; perhaps the external balance cranks have become a lot cheaper since the last time I compared them.

Big Dave
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post #8 of 14 (permalink) Old 09-17-2011, 08:48 PM Thread Starter
Join Date: Jul 2010
Location: Pine Island, MN
Posts: 18
In the process of planning on a 389 SBC build. I'd like to hear what the possible output of the motor will be (horsepower and torque wise). I'd also like to hear your opinions and suggestions on parts selection... Here's what I got...

ONLY parts I have thus far is a Block which is a machined Vortec 350 Bored 4.060". It was a fully machined block ready for rebuild from a crate engine maker that went under.
I am planning but getting really close to pull the trigger on bottom and top ends.

This will be a street car 67 Impala TH400, tall rear gear. Plan on building for cruiser nice kick ***** street cruiser not drag race bruiser. This is a low budget build. Please keep that in mind. not planning to turn past 6000RPM. So peak power at 5400-5700RPM max is fine
Looking for heads so far Patriot Performance offered me a super deal on the top end, heads, edelbrock intake Howards Hyd roller cam OE roller lifters, gasket match intake all top end gaskets and provide all gaskets and hardware.
here is current plan:
-67 Chevy Impala assume 4000+#
-TH400 auto with stock converter will change to match cam if needed
-3.07 rear tall gears stock tires right now figure 2000-2500 cruise RPM
The plan
-Want street car 80% hwy cruising 55-75mph, car shows may go on 200-300 mile cruises. Run on Pump gas 87-92 availiable. figure good low to mid torque cam to get big heavy car moving. On a side note I may take it to strip once a year for muscle car days. may change rear and tranny in time. This is only for fun cruising NOT drag car.
-We are at 1000Ft altitude if that makes a difference.
-'96-'97 SBC 350 block OE Hyd Roller 1 pc rear seal
-4.060" bore
-3.75" stroke
-trying to shoot for 0.038-0.45 quench
-10.1-10.35:1 CR
-most likely ext balance (on budget)
-Looking at Skip White's rotating assembly Scat 9000 Crank, PC rods, and Probe -12cc dish pistons. Comes balanced with rings, damper and flex plate. I really like the pistons and rods not sosure on the rods.
ebay link

Patriot Performance 190cc AL heads
Technical Specs:
Combustion Chamber: 64cc
Intake Runner: 190cc
Exhaust Runner: 62cc
Intake Valve: 2.02"
Exhaust Valve: 1.60"
Max. Valve Spring Lift: 0.575"
Spring Pressure Closed: 115 lbs. @ 1.800"
Spring Pressure Open: 310 lbs. @ 1.225"
Flow according to PP
I Flow
.100 66
.200 131
.300 195
.400 232
.500 252
.550 257
.600 260
E Flow
.100 54
.200 111
.300 155
.400 179
.500 192
.550 197
.600 199
(these # were provided by Patriot Performance on there new design they claim they have not updated there web page yet with new data)

-Intake Edelbrock #2601 dual plane Performer airgap
-Original Carb Quadra jet will be rebuilt
-Cam will be a Howards I have to provide spec to Patriot if I go that route. Howards reccomends : 180325-10
225i 233e @ 0.050"
278i 286e seat to seat
.525"i .530"e lift. with 1.5" rockers

Here is a link to all HOWARDS SBC OE roller cams IF YOU SEE ONE THAT IS BETTER FIT LMK.
-Lifters Howards OE Hyd roller

Here are a couple a questions:
1) What is you opinion will this be a good match up for the 67 Impala ?
2) The Vortec Bock is setup for OE hyd roller lifters is still better to run retorfit Hyd roller lifers ? can is even be done ? There is a $100 adder to go Retro Hyd roller lifters.
3) If I go kit route have not measured deck yet but will GM head gasket work with 4.060" bore GM 0.028 head gasket and will gasket work with AL heads ?
4) Looking at what Howards has to offer any you think would work better ?
5) For best bang for buck better deals on top end ?
6) Please feel free to give advice please control the mud slingin on heads.

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post #9 of 14 (permalink) Old 09-17-2011, 09:45 PM
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Jim, I really like that you took the time to put all that info down. Good on ya!

I gotta say, as I started reading this latest post of yours, it just reminded me of some similar questions I had for a 383 for my 66 Vert. We need great torque right, not big HP.
I'm not familiar with the Skip White kit but it sounds good and thought out.

I can say that I love Patriot heads and I really like the cam numbers for what you're doing. Patriots reputation is already made, they do know what they are doing, old heads or new. I saw that the cam is a dual-pattern with longer exhaust timing and slightly more lift.....I think that's great, especially if you decide you want the rams horn exhaust.
I do not like the Performer intake though. Yes, it does say it's for 0-5500 but unless something has changed over the years, it (had been) stock sized ports,...just made out of aluminum. Not to mention, it's not designed around 383 cubic inches, it was designed more around 283 - 350 cubic inches. I think you'd be better served with the Performer RPM or maybe even look to Weiand. I would not be surprised or upset if there's opposing opinions on this intake stuff though. lol.

On those roller lifters, I don't know any reason you wouldn't use the stock ones but maybe I'm not educated on some limitation they have relating to compatible cam profiles.
I think with the 10.0 - 1 CR and that cam that you're stuck with premium gas. Maybe it's possible to use a thicker head gasket to bring it .25 lower. Does the cam manufacturer recommend the CR that you mentioned up there?

I think that combo, depending upon your intake choice and exhaust manifold/header choice, is good for 380-420hp and 410 - 440 torque.

Will you be using an HEI distributor?

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post #10 of 14 (permalink) Old 09-18-2011, 02:23 AM Thread Starter
Join Date: Jul 2010
Location: Pine Island, MN
Posts: 18
Allan thanks here are my respounces to your questions
-Cam manufaturer sugested 10-10.5 with AL heads, 9-9.5 with IRON heads. Think the DCR will be around 8.3 ballpark not sure if this will work with 87-92 otane. When I sen the request to Howards I mentioned 87-92 octane.
-Not 100% sure on ignition I did see this on the Skip White web site and it peaked my inerest. It is an HEI

-on the intake it was what my carb guy reccomend, but he gave me a contact at Edelbrock to call and I will try him on Monday. Very good point. Goal is to get it right the first time around.
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post #11 of 14 (permalink) Old 09-18-2011, 07:54 PM
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I would recommend the RPM Air Gap instead of the Performer or the Performer RPM. It breathes as well as the Victor Jr. single plane up to 5800 RPM and only gives up a few ponies above that but makes 22 to 25 more foot pounds of torque across the whole RPM range than the single plane manifold. It is sized for a 190 cc runner already so it is a bolt on.

The factory spider spring and dog bone retainer have a valve lift limitation by design. Because as the cam lobes get taller the cam's base circle gets smaller (you can not get a big cam lobe past the cam bearings other wise; as the hole the cam fits in is fixed). As the cam's base circle gets smaller the lifters ride lower, and lower in the lifter bore. Eventually the cam is so small in diameter with a high valve lift that the dog bone retainers that keep the roller tappets aligned with the cam lobes slips off the top of the lifter allowing the tappet to rotate in the bore destroying the cam and the tappet.

Additionally the slot in the Vortec head for the push rod to come through is cut only long enough for a cam lift of 0.420 inch so it has to be machined as well (you can buy a self aligning cutter tool that will last long enough to cut sixteen slots to modify two Vortec heads for about thirty bucks). Then there is the issue of coil bind and the retainer hitting the oil seal on Vortec heads which is why I tell folks to either modify them or do like you did and buy after market heads (I only mentioned the limitation to inform other Vortec owners that the roller cam is only half of the problem). I do not know the absolute limit on valve lift with dog bone retainers (the roller cam design used stock by Chevy) but I have heard that it is about 0.520 inch is the maximum safe valve lift. Aftermarket lifters that go to 0.700 inches of lift or higher have slotted tie bars to keep the roller tappets aligned in the bores.

By the way Patriot buys raw castings from China and machines everything for the heads in Alabama on five CNC mills. Head porting, valve seats, and valve job, spring pockets, and valve stem guides are all cut by a computer so that every one is perfect. The heads are assembled and tested before shipping right in the deep south by fellow racers who like to go in a straight line instead of around in circles. They use quality American made Manley valves and valve train parts. High lift solid roller valve springs are sourced by PAC.

Big Dave
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post #12 of 14 (permalink) Old 09-18-2011, 09:31 PM Thread Starter
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Location: Pine Island, MN
Posts: 18
Thanks Dave,
-the cam is .525"i .530"e lift You think that is to much for Howards OE HYD Roller style do to the dog bone tray retainers will only support about .520" ?
I will definatly look into it I may elect to go retro lifters if they will work the block ?
-The 2601 is a Performer AIR gap not to good. DO you know of an AIR Gap RPM that will support a spredbore quadrajet ? Or is there a slolution for mounting a quadra jet to a RPM AIR GAP the only one I seen is #7501 which is a square bore for Holleys?
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post #13 of 14 (permalink) Old 09-18-2011, 10:01 PM
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The Performer RPM Q-Jet manifold is model number 7104 and is good for 1,500-6,500 RPM. It offers about the same performance level as the old Winters factory Z/28 manifold did as it is nothing more than a high rise aluminum manifold designed to accept a Rochester QuadraJet. That is the most advance manifold that Edelbrock sells for a Q-Jet. If you were to use a Q-Jet to Holley adapter you will increase the plenum volume (which aids high RPM operation at the expense of bottom end torque). Further it raises the carb three quarters of an inch higher which may get you into hood clear and problems on a Camaro or Chevelle, but I think the full size still has room under the hood. If you do have issues with hood clearance a dropped base open element air cleaner off a Corvette should solve that problem (though you rarely see hood scoops on full size cars as there is more room under the hood).

The Howard's cam claims it will work with factory parts, but I would get it in righting before buying it. They also have a very tight LSA of 106° degrees which makes for a peaky cam and might require an after market torque converter due to a lack of bottom end torque as a result of long cam duration. I thought I read were they recommended a 3,200 RPM stall. Need to read all of the foot notes to verify that is the cam you want, or at least post the grind number so we knoe excatly which cam you are looking at.

Big Dave
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post #14 of 14 (permalink) Old 09-18-2011, 10:22 PM Thread Starter
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Location: Pine Island, MN
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-Cam will be a Howards I have to provide spec to Patriot if I go that route. Howards reccomends : 180325-10
225i 233e @ 0.050"
278i 286e seat to seat
.525"i .530"e lift. with 1.5" rockers

posted the gind #180325-10
LSA I thought was 110. I believe IC is 106

Also doing more research to rebuild my Q-jet will cost as much as getting a new Carb. Sounds like it will be more advantaguos to go with the Edelbrock #7501 (Dave this is the on you reccomended THANKS). Talked Edelbrock twice and got two different carb opinions there both said to use #7501
First guy thought the Edelbrock #1806 650CFM AVS Thunder carb was the way to go and use #7501 intake.
Second guy thought the Edelbrock #1813 800 CFM AVS Thunder carb is the way to go and use the #7501 intake.

For max bottom end they thought the #2601 and Q-jet would work well but suffer up top a lot especially it being a 389 withthe heads and cam chioce.
SO I think a new carb is in order and I never had an Edelbrock never heard anything bad about them accept you will always make more power with a Holley. I see a 750 Performer rebuilt can be very reasonable but lacks the features of the AVS with adjustable secondaries. I am leaning toward the Edelbrock #1806 650 AVS unless can be convinced otherwise. my other option is to just go Holley 750 double pumper or Holley old list #3310 vac secondary. I seen an Edelbrock 750 Performer on sale as Jegs right now too. Any opinions out there please share.

Thanks for all the great input thus far.

Last edited by bowtieman427; 09-20-2011 at 01:28 PM. Reason: add info
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