Time to build up the 393 a bit more, next mod?

[1BAD351 21]

Well summer is almost here and I got the bug again… time for some more power. For starters my car has NEVER had good throttle response, so I think it's about time to get that fixed after almost 9 years of ownership. For starters, how good are my heads? I know they're not great, but is that something I should look into replacing, or is it not worth it unless I get into more serious power? I only run 8 degrees of timing advance, otherwise the car detonates. Should I try to shy away from the cast iron heads and grab some aluminum ones to help with this?

 

The car is an auto for now (C6), but I see a tremec 6 speed in its future, so lets build the engine assuming the car will be stick.

 

Some info on the engine off the sheet I got with it (started life as an Auto Zone HP signature series 393cid crate engine), I'll try to list as much of what's relevant that I can:

 

-351W (393 Stroker) using the 75-87 block

-Roush 200 Heads 2.02"/1.60"

-Adjustable roller rockers

-10:1 compression

-Flat tappet cam 230*/230* @ .50 Dur, 280*/280* Adv Dur .512"/.512" Valve lift, 110* lobe step (don't know much about what all this means, hopefully you guys do)

-Edelbrock 750cfm vacuum secondary 4bbl

-Edelbrock performance rpm intake manifold (thinking about pulling this for something better if anyone has any tips)

-Proform 50k Volt HEI Distributor

-headmean shorty headers

-2.5" mandrel bent exhaust with an H pipe

 

 

 

So what do you guys think? What direction should I go? Money aside for now (within reason) what would you guys go with? I'd like to get up around 500 HP (more can't hurt either). If there's anything I miss that would help to know let me know.

 

TIA

[1BAD351 21]

Well summer is almost here and I got the bug again… time for some more power. For starters my car has NEVER had good throttle response, so I think it's about time to get that fixed after almost 9 years of ownership. For starters, how good are my heads? I know they're not great, but is that something I should look into replacing, or is it not worth it unless I get into more serious power? I only run 8 degrees of timing advance, otherwise the car detonates. Should I try to shy away from the cast iron heads and grab some aluminum ones to help with this?

 

The car is an auto for now (C6), but I see a tremec 6 speed in its future, so lets build the engine assuming the car will be stick.

 

Some info on the engine off the sheet I got with it (started life as an Auto Zone HP signature series 393cid crate engine), I'll try to list as much of what's relevant that I can:

 

-351W (393 Stroker) using the 75-87 block

-Roush 200 Heads 2.02"/1.60"

-Adjustable roller rockers

-10:1 compression

-Flat tappet cam 230*/230* @ .50 Dur, 280*/280* Adv Dur .512"/.512" Valve lift, 110* lobe step (don't know much about what all this means, hopefully you guys do)

-Edelbrock 750cfm vacuum secondary 4bbl

-Edelbrock performance rpm intake manifold (thinking about pulling this for something better if anyone has any tips)

-Proform 50k Volt HEI Distributor

-headmean shorty headers

-2.5" mandrel bent exhaust with an H pipe

 

 

 

So what do you guys think? What direction should I go? Money aside for now (within reason) what would you guys go with? I'd like to get up around 500 HP (more can't hurt either). If there's anything I miss that would help to know let me know.

 

TIA

[RPM 1,190]

That should be a good motor. Usually throttle response is carb related.

[RPM 1,190]

That should be a good motor. Usually throttle response is carb related.

[Fordrevhead 29]

you need a good tuner, that engine should pull pretty well.,, doesnt sound like horrible combinations... 450hp easily. I would start with a local old school mechanic and a vacuum gauge. If there is an issue he can find it. Did you buy a shortblock and then build it up? A fair amount of flow can come from port matching the intake and head gaskets and ports as well as the exhaust side. Not worth pulling apart but if you ever change anything look into this.

[Fordrevhead 29]

you need a good tuner, that engine should pull pretty well.,, doesnt sound like horrible combinations... 450hp easily. I would start with a local old school mechanic and a vacuum gauge. If there is an issue he can find it. Did you buy a shortblock and then build it up? A fair amount of flow can come from port matching the intake and head gaskets and ports as well as the exhaust side. Not worth pulling apart but if you ever change anything look into this.

[MikeStang 247]

Humm....that thing should run really well, as stated above 400-450 hp sounds like where that motor should be.... Sounds like something is amiss......I would look into the old school mechanic if u can find a good one..... Sluggishness sounds carb related along with poss distributor issue.... May want to have that dist recurved.......whats your total timing at?

[1BAD351 21]

Yeah it goes, but it starts fallin on it's face at 5500-6k RPM which leads me to believe it's starting to get restricted earlier a bit too. But yeah nice guess, it's rated 400HP 440 ft lbs outta the box, so it's probably more now. But I have had it tuned and still no dice. I have a feeling the guy doesn't know what he's doing and I have stopped going to him for reasons I won't get into. But I figured I'd build it up a bit more and really get it rockin and then deal with dialing the carb in or buying the correct carb all together. I'll probably try to just learn it myself, I don't trust people with the car anyway.

 

I know the intake manifold didn't match up to the heads perfect when I did it, so that's another reason I was thinking of swappin the intake if there was a better one. matched to the heads or something.

 

I think this thing has a lot more power in it right now, but I can't put any timing into her. I really think there's a good 20 HP in timing right now maybe more. I've been thinking of upping the octane somehow (run 93 in it now) but my buddy has a 408 with 10:1 and he's makin 500HP no problem, but he has aluminum heads on his so has the timing pushed further.

 

As far as the engine, I only put on the intake manifold and VC and such, I bought it as a long block. Pretty stout little girl for being an auto zone engine haha. I have about 5k miles on the engine now and I don't go easy on it, so I suppose it's built halfway decent. Had it up a hair over 7k RPM once or twice (notttt on purpose) but point is it held together.

 

I really do wanna get 500+ ponies outta this thing, and I would like to run pump gas (93 octane) like my buddy does. I can't believe the 408 has all that much over my engine. Oh and believe me I'm not all about peak numbers, the girl moves down low too. His setup is similar to mine, but he's got better heads and intake. I really think the aluminum is helping his out a lot. Can't hurt to go on a diet either, wouldn't mind dropping some weight off the front end up high like that. What are your feelings on the heads? Keep them or are they restricting me?

[1BAD351 21]

Humm....that thing should run really well, as stated above 400-450 hp sounds like where that motor should be.... Sounds like something is amiss......I would look into the old school mechanic if u can find a good one..... Sluggishness sounds carb related along with poss distributor issue.... May want to have that dist recurved.......whats your total timing at?

 

When you say total timing you mean what I actually set it at with the timing light? If so that's at 8 degrees advance, anything past that and it detonates. The thing sounds good, idles nice, and pulls hard once it gets past that initial throttle lag. If you bring the rpms up and snap the throttle its not too bad, but when you come off idle I can damn near stall the car by hitting the gas too fast.

[BuckeyeDemon 211]

When you say total timing you mean what I actually set it at with the timing light? If so that's at 8 degrees advance, anything past that and it detonates. The thing sounds good, idles nice, and pulls hard once it gets past that initial throttle lag. If you bring the rpms up and snap the throttle its not too bad, but when you come off idle I can damn near stall the car by hitting the gas too fast.

 

increase the RPM and you will see it keep advancing. most people seem to talk mainly about total. mine wanted around 30-32 total with iron heads.

[1BAD351 21]

increase the RPM and you will see it keep advancing. most people seem to talk mainly about total. mine wanted around 30-32 total with iron heads.

 

How far do I have to bring the RPM up to see full advance?

[69gmachine 15]

How far do I have to bring the RPM up to see full advance?

 

That will depend on how the distributor is set up. It will determine both the total timing and when it's all in. For a performance street engine I'd say you should have all the timing in by 2300 rpm.

 

How much total you can use will depend on your head and piston shape as much as the material and even how it flows into the head to some degree. That's why it's best to have someone with a lot of experience set up the timing curves on the distributor. I used Ignitioneering to set up mine and I've been very happy with it. I'm sure their are many others that can do it as well.

Edited June 14, 2011 by 69gmachine
grammar

[1BAD351 21]

That will depend on how the distributor is set up. It will determine both the total timing and when it's all in. For a performance street engine I'd say you should have all the timing in by 2300 rpm.

 

How much total you can use will depend on your head and piston shape as much as the material and even how it flows into the head to some degree. That's why it's best to have someone with a lot of experience set up the timing curves on the distributor. I used Ignitioneering to set up mine and I've been very happy with it. I'm sure their are many others that can do it as well.

 

I suppose I will do that. First thing I want to do is get the engine setup where I'm going to keep it. Such as aluminum heads, new intake etc. before I get the final tune done on it.

[buening 63]

The stroker motors tend to like small single plane manifolds like the Vic Jr. That is a common intake for the 408w at least.

 

Regarding timing, don't forget to pull the vac advance line and plug it. My Duraspark dizzy is all in by 3000rpms and I have total timing at 34°.

[1BAD351 21]

The stroker motors tend to like small single plane manifolds like the Vic Jr. That is a common intake for the 408w at least.

 

Regarding timing, don't forget to pull the vac advance line and plug it. My Duraspark dizzy is all in by 3000rpms and I have total timing at 34°.

 

Really? Won't a single plane kill my bottom end?

 

Also do you mean pull the vacume line off the distributor itself and plug it?

[buening 63]

I'm by no means an engine guru, but the Vic Jr is somewhat common on a windsor stroker. The Vic Jr on a small block will kill the bottom end, but when you stroke it you are essentially turning it into a big block. Stroker motors LOVE to breath. I believe BuckeyDemon is running a Vic Jr on his stroker.

 

Yes, pull the vac line off the distributor and plug the vacuum line. The vac advance on the dizzy doesn't need plugged obviously. If you leave the vacuum hooked up to the dizzy, you'll have the vacuum advance during idle and you will get a high reading for your initial timing.

[1BAD351 21]

I'm by no means an engine guru, but the Vic Jr is somewhat common on a windsor stroker. The Vic Jr on a small block will kill the bottom end, but when you stroke it you are essentially turning it into a big block. Stroker motors LOVE to breath. I believe BuckeyDemon is running a Vic Jr on his stroker.

 

Yes, pull the vac line off the distributor and plug the vacuum line. The vac advance on the dizzy doesn't need plugged obviously. If you leave the vacuum hooked up to the dizzy, you'll have the vacuum advance during idle and you will get a high reading for your initial timing.

 

Ok I'll pull the line and plug the carb. Do you think my heads are restricting this thing? I was looking at the Vic Jr Heads and while pricey, they are oh so tempting. What kind of power increases do you think I would see from something like that along with the intake as well?

 

Also I think my headers are 1 5/8 do you guys think those are restricting any? I'd like to see a solid 400WHP or more out of this thing.

[Burn 14]

Your camshaft is rated from 2000-6000 rpms and probably why it falls on it face around 6200rpm. Your intake is rated from 1500-6500 rpm's and your 200cc heads want to flow over 7000rpm. For snappy throttle responce you may want to look into buying a carb with annular boosters. I bet the Edelbrock carb and Proform HEI is robbing you some HP too.

Edited June 15, 2011 by Burn
spelling error :P

[LoneWolf2U 136]

Well I'll toss in my thoughts even if it is a W ...:laugh:

 

The intake/carb/cam/headers are possiably holding you back.

Stroked eng like more air from a single plane, To keep some low end use a 4 hole 1in spacer under the carb for better air/fuel mixing before runners.

Carb while sized fairly enough the Eddy's are more of a street smooth carb and Holley will out perform them for power.

The cam could use more lift but if your using accessories like power brakes try and stay under .600 to have enough vac to operate.

While shorty headers make road clearence easier, they aren't much better than stock at pulling out the exhaust so long tube might make more on the power end.

As for the heads, even cast can be made to flow pretty good numbers with some porting work. Yes the Alum is lighter but so will your wallet be for possiably the same cfm flow.

[1BAD351 21]

Your camshaft is rated from 2000-6000 rpms and probably why it falls on it face around 6200rpm. Your intake is rated from 1500-6500 rpm's and your 200cc heads want to flow over 7000rpm. For snappy throttle responce you may want to look into buying a carb with annular boosters. I bet the Edelbrock carb and Proform HEI is robbing you some HP too.

 

How is the Proform robbing power?

 

Also my buddy has a double pumper 750 Holly thats literally only got 700 miles on it that he would sell me. Would that be a better carb for me to use? Thank I should snatch it up?

[1BAD351 21]

Well I'll toss in my thoughts even if it is a W ...:laugh:

 

The intake/carb/cam/headers are possiably holding you back.

Stroked eng like more air from a single plane, To keep some low end use a 4 hole 1in spacer under the carb for better air/fuel mixing before runners.

Carb while sized fairly enough the Eddy's are more of a street smooth carb and Holley will out perform them for power.

The cam could use more lift but if your using accessories like power brakes try and stay under .600 to have enough vac to operate.

While shorty headers make road clearence easier, they aren't much better than stock at pulling out the exhaust so long tube might make more on the power end.

As for the heads, even cast can be made to flow pretty good numbers with some porting work. Yes the Alum is lighter but so will your wallet be for possiably the same cfm flow.

 

Well when all is said and done, it is a street car so I should probably keep the cam under 600 then. I have been toying with the idea of getting a roller cam if you think thats a good idea. Lonmg tubes could be in the future I suppose as well and possibly a larger exhaust. What intake manifold would you reccomend? That might be a nice easy start to this along with the new carb.

[Burn 14]

How is the Proform robbing power?

I'm not sure it is, but how many 400hp plus 393w stokers do you see running HEI Proform's...

You'll probably be able to tune the Holley more than the Edelbrock. I'm using a Summit Racing 750dp with annular boosters and it's taking me some time to get it all tuned just right. As you know, an engine can lose a lot of HP by a poorly tuned carb.

[69gmachine 15]

Double pumpers are for drag racing only. If you really intend for this to be a street car, stick with vacuum secondaries. Personally I would ditch the Edelbrock carb. I tried one years ago and was never happy with the throttle response compared to an Autolite 600. Either get a Holley 3310 style or one of Summit's new carbs. I'm a big believer in annular boosters. I got exceptional mileage when I had a 351W and the Autolite, and I can't complain about the mileage I get now with my 735 Holley with annular primaries especially considering how big the engine is.

 

Don't get a Vic Jr. for a daily driver either. Yes it will post the best HP numbers, but you will have plenty of power with a 393 and a more streetable intake. If it were me, since you already own the Eddy RPM intake, I would have about half of the divider milled down to boost the mid range. The biggest streetable intake would be a Torker II. It will definitely lose a little some off the bottom, but I can live with it.

 

I'm not a fan of the HEI type dizzy, but I doubt it's costing any HP since your entire combo is designed to max out below 6K. Just make sure it's set up correctly.

 

Last, make sure you haven't wiped out a lobe on your cam. If you have and you need to replace it, consider stepping up to a hyd roller if you can afford it. It will allow a bigger cam to idle OK and have a broad flat torque curve.

 

I've been using my car with a 408 as my daily driver for the past 4 years when the weather is nice (and it's not down for some mod period).

[1BAD351 21]

I'm not sure it is, but how many 400hp plus 393w stokers do you see running HEI Proform's...

You'll probably be able to tune the Holley more than the Edelbrock. I'm using a Summit Racing 750dp with annular boosters and it's taking me some time to get it all tuned just right. As you know, an engine can lose a lot of HP by a poorly tuned carb.

 

That doesn't exactly answer my question haha. I don't see many 393W running around period. What would you recommend? When I bought it it was the only thing around at the time for the 351W.

 

Double pumpers are for drag racing only. If you really intend for this to be a street car, stick with vacuum secondaries. Personally I would ditch the Edelbrock carb. I tried one years ago and was never happy with the throttle response compared to an Autolite 600. Either get a Holley 3310 style or one of Summit's new carbs. I'm a big believer in annular boosters. I got exceptional mileage when I had a 351W and the Autolite, and I can't complain about the mileage I get now with my 735 Holley with annular primaries especially considering how big the engine is.

 

Don't get a Vic Jr. for a daily driver either. Yes it will post the best HP numbers, but you will have plenty of power with a 393 and a more streetable intake. If it were me, since you already own the Eddy RPM intake, I would have about half of the divider milled down to boost the mid range. The biggest streetable intake would be a Torker II. It will definitely lose a little some off the bottom, but I can live with it.

 

I'm not a fan of the HEI type dizzy, but I doubt it's costing any HP since your entire combo is designed to max out below 6K. Just make sure it's set up correctly.

 

Last, make sure you haven't wiped out a lobe on your cam. If you have and you need to replace it, consider stepping up to a hyd roller if you can afford it. It will allow a bigger cam to idle OK and have a broad flat torque curve.

 

I've been using my car with a 408 as my daily driver for the past 4 years when the weather is nice (and it's not down for some mod period).

 

It's a street car but not a DD, I put 5k miles on it in the past 8-9 years. I do also drag race it every month or 2 so I do want it to make some power. I'm only running mid 13's right now and that's just not fast enough haha.

 

I was just taking a look at this site because I wasn't sure what annular boosters were (anyone care to explain those? haha) and it looks like there's some good info here:

 

http://www.popularhotrodding.com/tech/0511phr_carburetor_boosters_tech/index.html

 

Why doesn't anyone like the HEI dis I have haha? I don't know much about tuning older motors or the physics of tuning engines in the first place to be honest.

 

Is this the manifold you're talking about? If so I'm willing to lose some bottom end to gain a lot up high. After I'm off the line the engine won't see less than 4k rpm anyway so I'd rather have more power up top. If I jump on it on the street I'm probably already moving so I would love the power up top, the car isn't in competition, its just for fun, so the 60 foot isn't THAT important to me. As far as on the street I'm not that worried about losing a little down low, I have some pretty bad traction problems as it is. Now I also assume the Torker II makes more power up high then what I have now even though both are rated up to 6500rpm as well?

 

http://www.summitracing.com/parts/EDL-5081/

[1BAD351 21]

Oh and this might be a dumb question, but what about my spark plugs; could they cause throttle lag? I just have regular old plugs in it. Do I need something hotter maybe?