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Discussion Starter · #1 ·
i have a STREET car 69 chevelle,1975 305,(29-3200 stall convertor) th400, and 3.73 rear.
I am on a budget, looking to put a 350 in with up to 400hp and torque. The late model vortec engines have a stronger bottom end than the earlier style engines.
Now, I dont have to get the motor to my hp and torque goals right away. At this point, I want that 305 out of my car. So Im looking to just put the motor in with a stronger bottom end. Then down the road change the top end.I can transfer parts from the 305 to this motor. My question is will a 1996-2000 vortec engine, be the right choice for a good foundation? Finding a remanufactered long block should be easy.
Also does it have mechanical fuel pump provisions?
 

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Discussion Starter · #3 ·
is a vortec engine a smarter reliable move? Will it support 400hp/tq without overly stressing the internals. I want to know if this motor is better as oppose to a goodwrench 350 for my goal.
 

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Any good 350 short block should be able to handle 400hp/tq. If you can I would try to get a block with roller cam provisions, 4 bolt mains, and flat top pistons. Those three things will give you a great set up to build a strong engine down the road. If you can I'd also spring for 6" rods, a nodular or cast steel crank, and the best balance job you can get. A high volume oil pump is a cheap upgrade and while it may not be absolutely needed, it's cheap insurance. If you can afford it forged pistons with a thin ductile iron or steel ring set are also great.

Getting all of the things I recommended will set you back a good amount, keep in mind there is a BIG difference between a run of the mill reman enigne and a top notch custom built engine.

Going cheap isn't a crime, but if you want to get something really nice I'd look for the things I mentioned. A 3.75" stroke may be a consideration too.
 

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For your stated goals the vortec is a great choice. The crank and rods are strong enough and the pistons are fine if you can get the compression to fit your needs. If you can find one with 4 bolt mains (1 ton) that's better but 2 bolts will work fine.
 

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i have a STREET car 69 chevelle,1975 305,(29-3200 stall convertor) th400, and 3.73 rear.
I am on a budget, looking to put a 350 in with up to 400hp and torque. The late model vortec engines have a stronger bottom end than the earlier style engines.
Now, I dont have to get the motor to my hp and torque goals right away. At this point, I want that 305 out of my car. So Im looking to just put the motor in with a stronger bottom end. Then down the road change the top end.I can transfer parts from the 305 to this motor. My question is will a 1996-2000 vortec engine, be the right choice for a good foundation? Finding a remanufactered long block should be easy.
Also does it have mechanical fuel pump provisions?
The Vortec is not fully machined for a mechanical fuel pump, it can be finished off however. The Vortec timing cover is plastic and does not accept changes to the OEM timing gears and chain without some effort. They can be backdated to a metal timing cover. The question gets to the cam whether you want to keep it a roller or convert back to a flat tappet.

The cylinder walls don't extend as deeply into the crankcase as older 350's which simplifies putting a stroker crank in there but also reduces some support for the piston skirt, this pretty much demands a hypereutectic casting or a VMS-75/4032 high silicon forging in order to minimize the skirt clearance so high accelerations from wide clearances can't happen when the thrust sides change at BDC.

I'm not impressed by GM's powder metal rod, I certainly wouldn't use it for any high performance application.

It seems you have a pretty high stall converter is this because the 305 is running a big cam? A 350 running Vortec heads, Performer RPM intake, Holly of 650 to 750 CFM, a Comp XE 268 or any of the aftermarket equals to these can easily get to 370 hp and with some tuning, porting, 1.6 rockers, big tube headers and certainly a 750 cfm carb will go to 400 or so. Piston choice plays big on the low through middle high RPM power. A D-dish or flat top piston in-place of the OEM round dish piston for a common compression ratio of 9.5 to 1 and holding the squish/quench dimension to not more than .040 really wakes up the middle RPM ranges with as much as 20-30 foot pounds of torque and 10-20 horses. The round dish piston output converges on the D-dish or flat top at peak RPM but under that the better piston really carries the day with a fatter power curve. This curve also carries a slightly higher power peak at a bit higher RPM with a slower decay than seen with the round dish piston.

Bogie
 

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Discussion Starter · #8 ·
The Vortec is not fully machined for a mechanical fuel pump, it can be finished off however. The Vortec timing cover is plastic and does not accept changes to the OEM timing gears and chain without some effort. They can be backdated to a metal timing cover. The question gets to the cam whether you want to keep it a roller or convert back to a flat tappet.

The cylinder walls don't extend as deeply into the crankcase as older 350's which simplifies putting a stroker crank in there but also reduces some support for the piston skirt, this pretty much demands a hypereutectic casting or a VMS-75/4032 high silicon forging in order to minimize the skirt clearance so high accelerations from wide clearances can't happen when the thrust sides change at BDC.

I'm not impressed by GM's powder metal rod, I certainly wouldn't use it for any high performance application.

It seems you have a pretty high stall converter is this because the 305 is running a big cam? A 350 running Vortec heads, Performer RPM intake, Holly of 650 to 750 CFM, a Comp XE 268 or any of the aftermarket equals to these can easily get to 370 hp and with some tuning, porting, 1.6 rockers, big tube headers and certainly a 750 cfm carb will go to 400 or so. Piston choice plays big on the low through middle high RPM power. A D-dish or flat top piston in-place of the OEM round dish piston for a common compression ratio of 9.5 to 1 and holding the squish/quench dimension to not more than .040 really wakes up the middle RPM ranges with as much as 20-30 foot pounds of torque and 10-20 horses. The round dish piston output converges on the D-dish or flat top at peak RPM but under that the better piston really carries the day with a fatter power curve. This curve also carries a slightly higher power peak at a bit higher RPM with a slower decay than seen with the round dish piston.

Bogie
the reason why im running a high stall convertor is, at the time i was having my TH400 installed I wanted a wicked big block so that convertor was picked according to the engine by the trans company. years later, I've decided to just keep it a small block for driveability and price.
 

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You can get a 96-2002 2 bolt longblock for $2200 and a 96-2002 4 bolt L31 longblock for $100 more.

-Roller cam equipped
-forged Powdered metal rods(stronger than the old Pink rods)
-nodular iron crank

With the cam that comes in it, 191º/196º 0.412"/0.428" 111ºLSA expect around 310-320 gross hp.

Great beginning for a nice street engine.

peace
Hog
 

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Then down the road change the top end.I can transfer parts from the 305 to this motor.
Be careful here. Bolting the 305 heads to a 350 block and using a short duration stock cam could raise the dynamic compression ratio into the threshold of detonation, depending on fuel quality. Resist any thoughts you may have of using two head gaskets to lower static compression ratio. That'll just make it worse.
 

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Discussion Starter · #11 ·
This would be my first 350 build. I would need a hoist, engine stand, and other tools. A crate engine might be a better choice for me. No guess work and you get a warranty. I'm thinking about the year one crate 350.
 

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Any good 350 short block should be able to handle 400hp/tq. If you can I would try to get a block with roller cam provisions, 4 bolt mains, and flat top pistons. Those three things will give you a great set up to build a strong engine down the road. If you can I'd also spring for 6" rods, a nodular or cast steel crank, and the best balance job you can get. A high volume oil pump is a cheap upgrade and while it may not be absolutely needed, it's cheap insurance. If you can afford it forged pistons with a thin ductile iron or steel ring set are also great.

Getting all of the things I recommended will set you back a good amount, keep in mind there is a BIG difference between a run of the mill reman enigne and a top notch custom built engine.

Going cheap isn't a crime, but if you want to get something really nice I'd look for the things I mentioned. A 3.75" stroke may be a consideration too.
I'm with you until you get to the 6" rods and needing a 4 bolt main.Ring spacers because of pin placement and mm ring sizes for long mileage use on the street isn't what I would suggest.Two bolt blocks for street use at 400 hp would be fine.If later he wanted more,he could go the splayed mains which would be a much stronger part than a OEM 4 bolt.
 

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I don't think,given you saying the plan was for a BBC in the beginning,your ever going to be happy with any SBC.Sometimes your first gut feeling is the right one.And in this case I think your right.

Here is what I suggest you do before you spend the time and money on a SBC.Call Pat McCarthy of McCarthy Performance.Techinspector1 would agree with me he builds some of the most rightest BBC's at very reasonable prices.It is kind of his specialty.Do talk to Pat and if you like,tell him I told you to call.

McCarthy Performance / Racing Engines to 632+ Cubes

He'll build you a pretty shout SBC too if you like.
 

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I'm with you until you get to the 6" rods and needing a 4 bolt main.Ring spacers because of pin placement and mm ring sizes for long mileage use on the street isn't what I would suggest.Two bolt blocks for street use at 400 hp would be fine.If later he wanted more,he could go the splayed mains which would be a much stronger part than a OEM 4 bolt.
If you're going splayed caps you may as well go SHP, a 4 bolt block can be had for the same price as a 2 bolt and it has added strength.

With a 3.48" stroke the support rings aren't needed, the 6" rod does require support rails on the oil ring with a 3.75" stroke, which is no problem and common for some engines, the pistons should be bought for metric rings so spacers are not required.
 

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Metric low tension ring sets do not have the same sealing capabilities as a standard set.They are more appropriately used in a race set up where drag tension is a concern.I don't want to open the topic of long rod vs short rod debate.I in fact believe in the use of long rod engines.What get's more complicated is whether the trade off of ring spacers is worth the long rod in a relatively low compression street application.I'm saying it isn't and in fact the longer rod (6" vs 5.7")isn't going to make that big of a difference.That we build long term good sealing street performance street engines that are reliable.
 

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Metric low tension ring sets do not have the same sealing capabilities as a standard set.They are more appropriately used in a race set up where drag tension is a concern.I don't want to open the topic of long rod vs short rod debate.I in fact believe in the use of long rod engines.What get's more complicated is whether the trade off of ring spacers is worth the long rod in a relatively low compression street application.I'm saying it isn't and in fact the longer rod (6" vs 5.7")isn't going to make that big of a difference.That we build long term good sealing street performance street engines that are reliable.
metric ring sets seal BETTER- which is why OEM's have been trending towards thinner rings for decades. and as I already noted a 6" rod DOES NOT require oil ring support on a 3.48" stroke. If you need new rods and pistons there isn't a single reason in favor of a 5.7" combo.
 

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metric ring sets seal BETTER- which is why OEM's have been trending towards thinner rings for decades. and as I already noted a 6" rod DOES NOT require oil ring support on a 3.48" stroke. If you need new rods and pistons there isn't a single reason in favor of a 5.7" combo.
AP- I am going to respectfully disagree with you on the ring sets long term and I know with 3.48 stroke as oil ring spacer isn't used,so in that case a 6" rod could be used.I did think I read he was if with a SBC going to stroke it.

As I posted,I suggest he goes with a BBC.
 

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AP- I am going to respectfully disagree with you on the ring sets long term and I know with 3.48 stroke as oil ring spacer isn't used,so in that case a 6" rod could be used.I did think I read he was if with a SBC going to stroke it.

As I posted,I suggest he goes with a BBC.
I appreciate you being civil about the ring issue, but all of the data collected by all of the major car manufacturers shows that you're wrong. They're switching to thinner rings for a reason- more power, better sealing, less bore wear, and as a result better emissions. Many of them are also switching to steel rings (a lot of foreign cars have used steel rings for decades).

The singular advantage thicker rings have is cost. for sbc's a cast iron 5/64ths ring set is still the cheapest set by a LONG shot.
 

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I appreciate you being civil about the ring issue, but all of the data collected by all of the major car manufacturers shows that you're wrong. They're switching to thinner rings for a reason- more power, better sealing, less bore wear, and as a result better emissions. Many of them are also switching to steel rings (a lot of foreign cars have used steel rings for decades).

The singular advantage thicker rings have is cost. for sbc's a cast iron 5/64ths ring set is still the cheapest set by a LONG shot.
This is true but it's all being accompanied with changes to better materials inclusive of the ring, piston and bore, reloacted ring positions and changes not only to oils but lubrication systems as well. So retrofitting this technology into old engineswill take a coordinated effort to make changes that let this modern stuff survive. It just might not be possible to get away with in a thin wall gray iron block without some "Rocket Science" changes to the bore materials and a heavy duty redesign to some details of the lubrication system like indexed squirters onto the underside of the piston. This can easily take you down a crazy road that the average hobbest hot rodder that comes here for help probably doesn't have enough VISA card limit to be able to afford this modern stuff.

But by any current standard the 5/64th ring package is way obsolete. But there must be a bazillion leftover pistons that were originally made back in the 1970's still on the market with this groove width. If your not turning over 6000 RPM, feeding the thing laughing gas or methanol these old rings will still get the job done for the average guy's budget.

Bogie
 

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Just saying "metric rings" leaves a lot out of the picture IMHO. There has been metric rings used in GM production engines for quite some time now- including the Gen 1 and 2 SBC. So to say 'metric rings' does not necessarily say anything is all that different that can't be handled by a competent machine shop (tension, materials, honing finish) other than the measurement system used to measure the rings. In the case of the SBC the top rings measure the same thickness for all intents and purposes, while the second rings are marginally thinner than the old fractional ring sets.

Example:

A 5/64" ring = 1.98mm. The LT1/4 Gen 2 engines and the later Gen 1 engines use a 2mm/1.5mm/4mm ring package. The second ring is akin to a 1/16" fractional ring. Radial tension may be less, but it does not HAVE to be so.
 
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