Large Vortec bowtie, Engine?

General engine tech -- Drag Racing to Circle Track

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88bluestar
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Large Vortec bowtie, Engine?

Post by 88bluestar » Wed Sep 12, 2018 6:15 pm

Current engine is a 355 sbc, large Vortec bowtie heads(215cc I think) with bowtie raised runner intake,780 Holley SMI race carb on 91 octane, 9.8:1 compression
6.125 Honda rod end, 45 lbs 4340 crank with low piston and metric ring set. 252/255 4/7 custom Comp cam
Seem to have decent power but larger head really hurts torque wise but also rod size and maybe the cam.

Engine rule is as below
360 cid max 9.8:1 ratio max
Any intake but carb mount surface is 7” max from block to intake carb mount, any 4bbl carb.
.540 intake/.560 lift rule(solid flat tappet)
7000rpm rule. Any header allowed

Hoping to get proper heads etc on engine during winter.

My question is, if I’m unable to sell the larger head, what suggestions as far as a back up engine with this head, what would you suggest to make the best of the situation?

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Re: Large Vortec bowtie, Engine?

Post by zums » Wed Sep 12, 2018 7:47 pm

The LPVB is a good head but still needs work, if it were mine i would shrink the bowl, that area of the head is large compared to the rest of the port and will give a considerable speed difference from pinch to bowl , depending on your target mach i show roughly 2.13 avr csa considering 7000 , the LPVB is around 2.42 untouched, "if" its 215, alot of them are 223cc {2.52},- head is too big for your comp and rpm
Tom

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Re: Large Vortec bowtie, Engine?

Post by rustbucket79 » Wed Sep 12, 2018 10:35 pm

More information required.

Oval track engine?

RPM rule hurts your combo for sure. Less cam duration might help, as well as other aspects of the engine and car. What are the fast guys running for heads in your class?

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Re: Large Vortec bowtie, Engine?

Post by 88bluestar » Wed Sep 12, 2018 11:06 pm

1/4-3/8 mile clay oval track, dryslicks often but still traction up high and on the bottom. I have a feeling that some fast cars are running either a small runner VB or EQ type small runner head, roughly around 185-190 cc runners.

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Re: Large Vortec bowtie, Engine?

Post by 88bluestar » Wed Sep 12, 2018 11:12 pm

The large VB I have are last 3 digit- 371C and gather they have 2.02/1.60 valves. They look to have been manufactured in 2007.
2203 stamped on the accessory end of the head then below it 14 02 07
Engine was originally built in 2008 according to previous owner and had seen limited races on it so I’m pretty sure the 02 07 might mean February 2007? If so was this a 206cc or 215cc Head?

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Re: Large Vortec bowtie, Engine?

Post by F-BIRD'88 » Wed Sep 12, 2018 11:35 pm

Why not try added intake port floor tongues in the intake ports if you want more port air speed.

88bluestar
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Re: Large Vortec bowtie, Engine?

Post by 88bluestar » Thu Sep 13, 2018 1:44 am

Like a turtle? Or do you mean extensions on the ports extending into the center under the carb?

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Re: Large Vortec bowtie, Engine?

Post by Frankshaft » Thu Sep 13, 2018 9:40 am

Can you run methanol? That would boost tq. And no, it doesn't have to be high compression. Engines like yours really pick up tq with it.

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Re: Large Vortec bowtie, Engine?

Post by 88bluestar » Thu Sep 13, 2018 11:01 am

Might be able to run E 85 possibly but not sure about methanol

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Re: Large Vortec bowtie, Engine?

Post by F-BIRD'88 » Thu Sep 13, 2018 12:37 pm

Picture a plenum turtle with 8 long legs. Port floor tongues.

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Re: Large Vortec bowtie, Engine?

Post by steve cowan » Thu Sep 13, 2018 7:28 pm

My question is, if I’m unable to sell the larger head, what suggestions as far as a back up engine with this head, what would you suggest to make the best of the situation?
[/quote]

88- this is your original question that you asked,
first you need to capacity check the intake and exhaust ports and establish what you are working with,is it 215 cc or a 225cc ??
2.00''in - 1.55''ex valve size ??
2.02''in - 1.6''ex valve size ??
are the heads ported or untouched ??
you said you are purchasing a smaller head to suit your short block,makes sense to me.
if you keep these cylinder heads and build a spare engine you are already governed buy the rules in place.
TOM (ZUMS) has already mention in his post the average cross section of the intake port for your short block,RPM,COMPRESSION,CAM,LIFT RULE etc,so unless you reduce CSA through the entire cylinder head intake port and possibly exhaust port depending on the size,you have a engine with no power off the turns,head to BIG.
are you able to epoxy and port the cylinder head yourself or do you have to pay a professional to do the work??? COST
is it worth the time,labour and effort and cost,probably not in your application,was this engine bought with the race car or how did it come about,if you had more compression,lift and intake height the motor would make good power but rules are in play here.
F-BIRD'88 wrote:
Thu Sep 13, 2018 12:37 pm
Picture a plenum turtle with 8 long legs. Port floor tongues.


F-BIRD,
i dont want to sound abrasive here but i have seen you mention this over the years and you need to show me this turtles tongue thing you keep going on about,i just cant see how its even possible to correct an intake tracts AVERAGE CROSS SECTIONAL AREA with this setup you keep talking about,even if it was possible to engineer how do you retain it,all i could see is it turn into a mess with reversion and wave reflection pulses in the intake port,i have read where people have tried crude dividers in single plane intakes and they have been torn out in a running engine,
F-BIRD- you need to show me something you have made and used and show me the positive or negative results or i am calling it a wash..............
steve c

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Re: Large Vortec bowtie, Engine?

Post by groberts101 » Thu Sep 13, 2018 7:46 pm

Google Brodix turtles and you can get an idea of the various designs. None that I've ever seen or used have nearly long enough legs into the entry of runner floors to do anything remotely positive towards substantially increasing port velocity. And even if you did find something shaped with longer legs.. getting them inserted into the plenum and clocked into position seems near impossible not to mention how delicate the ends would be once tapered out.

Their intention is to liven up plenum floors through texture, fuel shearing and angular changes of floor shapes.. not runner volume displacement.

IMO, you could bandaid the situation with slightly advanced ICL and smaller intake runners but that will only get you so far towards higher head port velocities.

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Re: Large Vortec bowtie, Engine?

Post by 88bluestar » Thu Sep 13, 2018 8:00 pm

It’s my hope that there is a market for these heads when the season concludes and sell them once I’ve had them cc”ed and gone over so I have proper flow numbers etc to show a potential buyer. The intake is a raised runner type to match the head so it’ll have to go as well.

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Re: Large Vortec bowtie, Engine?

Post by steve cowan » Thu Sep 13, 2018 8:19 pm

88bluestar wrote:
Thu Sep 13, 2018 8:00 pm
It’s my hope that there is a market for these heads when the season concludes and sell them once I’ve had them cc”ed and gone over so I have proper flow numbers etc to show a potential buyer. The intake is a raised runner type to match the head so it’ll have to go as well.
sounds like a good plan,if you are willing to spend the time on the forum here,i suggest Google Search or read through some old posts,there will be excellent engine builders here that if you send them a private message most are willing to help steer your combination in the right direction to work within your expectation and budget,good luck with it.
groberts101 wrote:
Thu Sep 13, 2018 7:46 pm
Google Brodix turtles and you can get an idea of the various designs. None that I've ever seen or used have nearly long enough legs into the entry of runner floors to do anything remotely positive towards substantially increasing port velocity. And even if you did find something shaped with longer legs.. getting them inserted into the plenum and clocked into position seems near impossible not to mention how delicate the ends would be once tapered out.

Their intention is to liven up plenum floors through texture, fuel shearing and angular changes of floor shapes.. not runner volume displacement.

IMO, you could bandaid the situation with slightly advanced ICL and smaller intake runners but that will only get you so far towards higher head port velocities.
thanks GR,
yes i am familiar with the plenum turtles all though i have never used or seen them up close,my point was more about using a shoe horn in the intake runner in this application,but i think you get what i am saying
steve c

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Re: Large Vortec bowtie, Engine?

Post by groberts101 » Thu Sep 13, 2018 9:03 pm

steve cowan wrote:
Thu Sep 13, 2018 8:19 pm
thanks GR,
yes i am familiar with the plenum turtles all though i have never used or seen them up close,my point was more about using a shoe horn in the intake runner in this application,but i think you get what i am saying
Yeah I got the gist of it, Steve. And most intake runners don't have nearly enough taper to get away with substantially shrinking the entries anyways. You'd just end up with a reverse taper which is obviously the wrong way to go about building and shaping an intake runner.

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