Welcome to the next installment of the

Topic of the Week
to run from 3/22/02 to 3/29/02

The subject for the week is all about TBI engine's heads and matching intakes.

Some suggested points of discussion:
- What heads people have used with TBI engines
- Track improvements
- Costs
- Final Compression
- how milling and decking affect how parts go together
- porting and polsing
- Boring intakes
- TBI to carb itnake adapters



Lets see lots of pictures and track improvements =) this week.

 

I'm feeling lazy right now so I dont want to post the pics but if you want to see a comparison between the LG4 vs. L03 vs. World S/Rs go to this post: https://www.thirdgen.org/techbb2/sho...threadid=92996

You will get a good idea of how these heads compare in the chamber and intake ports.

 

Oh and check out this link for useful flow data:

http://www.nastyz28.com/2gcog/cylhead.html

Things to take into consideration for heads for most power:

Spark plug placement inside chamber

Valve centerlines

Intake volume and length

Exhaust port angle and length

Can these things be ported at all?

 

How 'bout simplicity and ease of installation? Those are my 2 biggest concerns. It seems from all the forums in here that S/R torquers are the way to go???

 

ok since ive decided to stick with tbi and 305 which some say is worse and worser, i am going to make the best of it because as ive stated before my little 305 has been very forgiving to me. Im going to stroke it and bore it .30. I want to use the 400sb crank which i think would make it like a 337? My question is what heads will flow best with a setup like this? Even if I was to purchase heads first id still like them to be able to work with my stocker now and the stroker later? Im in the process of saving like 3000 just for my 305. Im getting a new t5 from gm thats running me $2300 installed. sticking with that because they give me a 3yr or 50000 mile waranty. 5 gears is enough for me. ill probablybe passing this car to my son so $$ is not a problem. its just saving for it. So with some good heads 3.08 posi and about 3000 in the motor. i outta be hell in about a year or two.

 

i was wondering if anyone has flow numbers of tpi 305 heads... they are the cheapest heads you can get i would think from a junk yard.. i am wondering the cost of porting them and flow numbers of them.. maybe that would be something i could find on a tpi board but hey this is the topic of the week...

i am just here to learn...:lala:

 

I was looking at the numbers on that flow chart for a vortec head . I dont know if this is supposed to be a L31 vortec head, but it lists the flow at .500 lift. The max lift for a L31 head is listed at .480 unless it is modified. Some one on this board broke some stuff at .480 lift and says its more like .470 lift max.

 

I've looked everywhere and I havent been able to find #'s on these heads...maybe someone else has and they can speak up?

The problem areas with the 305 TPI heads have 1.84 intake valves (most others like the LG4s had 1.71 intake valves) so there's not as much flow as a head with 1.94 and the spark plug placement seems to reflect 70s technology with the recessement and the fact that the plug sits offset from the center only slightly to the intake valve. In all honesty you probably wont see much of an improvement with these heads over the 187s...maybe 10-15 horsepower when ported, although you will see a wider powerband, but not much more overall power.

 

Are you looking to keep your emissions equipment? If not then the only things you have to worry about in ease of installation is the two middle intake bolts and the center or perimeter valve cover bolts. If you are wanting to keep your EGR, then the Vortecs and L98 Aluminum heads are the ones to stay away from for ease of installation and go straight for the World Products S/R 305 Torquers because they bolt right up with no problems at all. Just pay attention to the different intake patterns with these heads: 87-95 the two middle bolts are more upright; pre-86 all the intake bolts are the same angle. These heads can be also ordered with perimeter valve cover bolt holes or center; and just a recommendation for you; stay with centerbolt valve covers, because perimeter bolt valve covers leak like crazy.

 

How much are you willing to spend?

 

Its just a matter of changing the valve springs. The springs are only rated at .450" max lift.

 

Thanks for clearing that up iroc22. I wasn't sure what the clearence problem was.

I'm in the middle of porting and polishing a set of S/R Torquers. I finished one head this morning. I think I'll clean it up and re-asemble it before I start the other one. That way I get to take a break from grinding for awhile. For the most part there is not much to remove anywhere, just mainly polishing. The one area that really needs some attention is directly behind the exhaust valve seat were there is a good sized ridge all the way arround. Gasket matching was hardly necessary. All in all I'm happy with the quallity of the castings and the machine work both. One thing I need to do is run a hone stone arround on some of the edges and break the edge slightly, they are awfully sharp.
later, Dave

 

I'm happy with my choice of heads(S/R torquers with 58cc chambers). They come with Manley valves, screw in studs, comp cams guideplates, umbrella seals, .560 lift, and adequate spring pressure for the cam I will be running (ZZ4). You would spend more money buying, milling, and modifing a set of vortec heads to be comparable. Not to mention a vortec manifold costs more.
HOWEVER, you would have less valve shrouding with the voretec's larger shaped chamber. That is something to consider. You cant get away from valve shrouding with 58cc chambers. The need of a small combustion chamber seems to be the bigest draw back in building a 305.
HOWEVER, the ZZ4 seems to make good power with 1.94 valves and 58cc chambers. It probably helps that they are sitting on a 4.00" bore.
Later, Dave

 

Im looking at getting the 330hp 350ho engine this summer and i am wondering which intake manifold best fits my needs.

Unfortunately i have emissions here in vegas so any type of superperformer is out of the question. I was either looking at the vortec intake manifold, the edelbrock performer, or the edelbrock vortec. THe problem is im not sure whats involved in plumbing the gasses from the exhaust manifold to the intake manifold for the vortec, im not completely sure if the edelbrock performer matches the vortec heads, and im not sure if the edelbrock vortec has egr?

Im looking for the best manifold that will pass emissions and give me the best performance.
Mike

 

The World heads are the greatest head for the $$ because they come with such high quality parts. They definitely are a good choice.

Most Vortecs even though they are rated at 64cc from GM, most of them are around 61cc so they almost match the 305's 58cc. But the Vortecs just have that excellent high quench design that frees up a lot of room around the exhaust valve allowing the hot gases to exit the chambers much faster.

You'll find that the flow #'s on the L98 aluminum heads and World S/Rs with the 1.94/1.5 are close to the same. The intake #'s are slightly higher on the Worlds but they will make about the same power levels on the dyno.

 

I've got a set of aluminum L98 heads on my 305. I got 'em ported through SDPC. They've got pretty good flow numbers, not the greatest, but pretty good. Check my website if you wanna see 'em.

 

as far as the heads go.....around 500. I want to be able to port and polish and the 3angle valve job andall that good stuff.

 

So I get from your response that you want to go with a factory used set of heads then? Well the best would be TPI heads from a 305 probably or the L98 Aluminums from a 87-91 or 86 vert Corvette. Remember if you get the 305 TPI heads to put some 1.94 intake valves on them.

 

World data"
@.500 lift intake 213, exhaust 166
@.400 lift intake 198, exhaust 156
this is almost as good as mark's ported
corvette heads and the I/E ratio is
much better than the vortecs
world: 78%
l31: 66%

 

I went for the pre 87 S/R torquers because the 87 and newer were back ordered every where I checked. They were only $310 apiece for the 86 and older heads at Jegs with free shipping ta boot (saved me over $100 compared to the 87+ heads). I will have to slot the center holes on my TBI performer manifold to make it work. But in the future if I buy a carb manifold it will save me even more money for the older stile bolt pattern. These heads come with tapped holes for both centerbolt and perimeter bolt valve covers. After much thought I,m going to buy perimeter bolt covers for 3 reasons. First, way better selection. Second, cost about half as much. Third I am going to go to full roller rockers and most of them dont work with center bolts. Only draw back is they are more prone to leak.It will be awhile before I install but I'll keep every one posted.

 

I'm interested in the TPI heads, as I don't want to throw a lot of money into my 305.
I figured the best way to get this info would be to ask they guys that have them stock.
I posted a general question on the TPI board at https://www.thirdgen.org/techbb2/sho...threadid=94514 and hopefully, we'll get a few responses with some good info.

 

I thought I'd throw you all a bone. Here are some flow numbers for heads with 180cc or smaller intake ports. This should help everyone a little. http://www.chevyhiperformance.com/ed...1599&sidebar=1

 

the GM "deluxe" crate motor which has 330hp has vortec heads so youll have to run a GM vortec manifold or a manifold made to fit vortec heads...im thinking about going ahead and getting S/R 305 torquers and eventaully putting them on a 350 guys over on the tech board seem to think it will work well and help reduce valve shrouding...will make some nice compression tho id say in the 10:1 range like the zz4 has...my question is could i run n2o with that kind of compression...oh and it will probably be on a l98 shortblock...1100$ for the whole rotating assembly...thats why im gonna go with that...cheap...anyways is that to much compression for a power adder?

 

That L98 shortblock come with a cast crank, that high of compression along with n2o does not sound like a nice combination to me. Now if you spend an extra 700 and get the ZZ4 shortblock you may be able to pull it off.

 

That shouldnt be that hard cause Edelbrock makes some great manifolds designed for the Vortec 8 bolt intake pattern.

 

um no. The weak point are the non-forged pistons. They're the same on both so the extra bolts on the main caps aren't even an issue. But of course it depends on how much you use the nos.

 

The ZZ4 shortblock actually has hyper pistons, which could POSSIBLY be better for nitrous.
Of course, say that around an old timer, and they'll give themselves a heart attack arguing with you about how hyper pistons IMMEDIATELY break, even when in the general vicinity of n2o.
At any rate, no the pistons are not the same between the L98 and the ZZ4.

 

I'm pretty sure the hypereuritic pistons are a weak part of an N20 system. Forged would be definitely a safer route.

 

They might not be exactly the same but they are made the same way. Hypereutectic(sp?) pistons. Better than cast alumium but not as good as forged pistons.

 

Hey I just wanted to let everyone know here that I just found something out that's really important.

I pulled a set of heads off of an LG4 Camaro and I have been researching the casting #'s. Turns out that the 416 "H.O." TPI heads were actually used from 80-86 and in almost all 305 engines. The actual 87-92 305 TPI heads were actually just an updated design of those same heads with raised valve covers and centerbolt valves. They have always been 1.84/1.5 valves.

 

Hot Rod magazine had the same problem with the buildup of their GM HT383. They said you can trim the inner ribs on the valve covers to clear the roller rockers or buy after market valve covers (can't remember who makes 'em) without the ribs.

 

ok.. let me ask this question since i see heads is the topic of the week. im finsihing up the improvements on my 305 tbi wth a set of ported and polished heads but before i put them on this weekend i had i question.. i know there 58cc but what i i had them milled to 56cc how far would that boost the compression ratio and would i notice and extra performace b/c of this or is it not worth alot ..i can get it done cheap so cost is no object.. enigine has around 55k on it right now..

thanks

 

I have some questions also. I wanto know what the best heads are. Price to performance. The World Torquers? I want to be emissions legal, but If I get new heads, what else would it require, porting, polishing, valve job, etc...? I'm kinda new at engines, but I'm helping my friend put a set of redone 351W heads on his old 302, and it doesn't look that difficult. How difficult is it to do? could it take a weekend to do it, or more?

 

The World Torquers are definitely the best emissions compatible heads out there. It's easy to swap the heads too. And the best part is they can just be bolted on and you're ready to go. They work great as delivered but you can port and polish them for more performance, but it isnt necessary.

 

Guys,

Can't say enough good things about the TFS 23d heads. Well made, easy bolt on. With 64cc chamber and 195cfm ports, they work very well with my Xfire motor and manifold.

 

It's obvious u must've swapped for a 350
seeing that ur chambers are 64ccs. and an intake
port that size would kill the low end of a 305

 

Ride,

All Xfire Vette's are 350's. Sorry if I didn't post that part.

 

Didn't know u had a vette.

 

Whats the difference between the World Torquer and the World S/R Torquer Heads
What if I put one of the above 305 heads on my 350??? I have 305 LO3 heads on it now

 

World is the name of the company. S/R Torquer is the model of the head. The L03 heads stock have the 58cc chambers so to keep the compression you're running right now, you gotta get a 58cc head. The S/R Torquer 305 heads are smaller valves than what u can put on a 350. Go with the S/R Torquer 67cc heads because they have the 2.02/1.6 valves for the best flow.

 

Great information guy!!
I am still debating whether or not to take the heads off my 89 and put them on my 90. It would be a lot of work and cash, another motor might be in the plans.

I had one question kind of related. Are the exhaust manifold any different between TPI and TBI? I was going to put my 3" cat back system and random Cat on my car last weekend when I put in the 98 M6 rear end and spohn LCA's and SFC's, but the Y pipe on TBI is ridicously puney!! It can not be bigger than 2 1/4 if not 2". I really don't think at this stage of the build up that headers would make a big difference, so I just want to swap out Y-pipes (Actually, I need a new TPI Y-pipe, the 89's is cracked) Is this possible?

Thanks,
Mike

 

Yeah the actual size of the Y-Pipe and manifolds differ the TPI got the 2 1/4 outlet manifolds with 2 1/2 Y-Pipe (if it's the single cat system) The TBI's manifold outlet is 1 7/8 with the same size down pipes with 2 1/4 I.D. Y piping.

Swapping between the two systems is very doable and you should see a big increase in acceleration. The ultimate still is a aftermarket high flow Y-Pipe with tubular headers.

 

Usefull info. I love it. Thanks Iroc22. I downshift this thing and can actually feel how restricted the intake and exhaust is. It is unfair to compare TPI to TBI with such a big difference in flow. I bet I could dop .3 to .4 off the 1/4 by the swap. When I ran it bone stock with a peg legged 2.73 rear, I turned 16.7. How can ya call it a sports car when I could be taken by any given honda with a coffee can muffler.

Anybody got some used TES for sale??

 

Yes this is very true. You cant just look at the #'s on the paper.

 

anybody know if i could use the ex manifold and y-pipe

from the BUBBLE style body caprices?

on my L03/tpi heads

anybody know the size?

 

The 92 and 93 TBI Caprice cop cars (9C1s) got a big 3" Y pipe but I wouldn't use the manifolds. They're pretty sucky, I think. The Y pipe and cat setup isn't bad though.

 

What's the casting number on the 86-91 aluminum corvette heads?

 

Just by putting a set of el cheapo Dynomax headers with 2 1/2" collector, 2 1/2" y-pipe(cat deleted), and 2 1/2" exhaust with a flowmaster 80series muffler, i picked up .735 and 9mph in the 1/4 average on a 305 STOCK motor with a K&N air filter in stock cleaner housing. This motor(like yours) had the TH700r-4 with crappy 2.73 gears. I was running 15.3's with 5.15-5.20 r/t and crappy 2.4sec 60fts Peg-leggin off the line