JeepCycle

I am at a crossroads. I have the TPI off my 85 w/5.7 Crate motor w/World Products S/R heads, ( all of which was put in by P/O), to install new bosch injectors. I have the opportunity to get a complete, running 5.7 Vortec engine with the 062 heads.
I have long tube headers, with good flowing exhaust system.

Which will give me the best power increase with the most reliability?

My original plan was to use the vortec heads w/ 1.6 roller rockers, edelbrock intake and tubes.

Would I be better off changing to the 4-bolt vortec engine as a whole and then going to the edelbrock components w/1.6 rockers?

I'm not trying to have the fastest car, just get it to a point where it doesn't run out of breath and power at 4-4.5k RPM. As the prices are about the same, I just want the best bang for buck with this list of choices.

Thanks for

cv67

I would not swap an entire motor over to use the vortec (overrated) heads. A 2 bolt is fine.
Youll need to upgrade your TPI to keep it from hitting the infamous "wall" of 4k. Cam for tq not hp

JeepCycle

Thanks for the lighning fast reply.

I am a bit confused though. As I thought I understood from many threads on the forum, the l98 has semi-descent tourque but had low HP because it ran out of breath due to pollution control items, heads and tpi. Valvetrain lift and duration were a bit low to for a high performance street machine.

My real aim is not stoplight racing. I am hoping to get a little more mid and high range power. I'd like the power increase in the 2500-5500 range. Once again, this doesn't have to be a rocket, just something I can enjoy on a newly paved backcountry twisty.

Are you saying that the 062 vortec head isn't a better bang for the buck than porting say old camel hump heads?

RWDsmoke

i used to run a vortec motor in my 86. Made very good power, 10:1 cr and on 87 octane gas. If the motor is right out of a truck it has very weak valve springs and not much cam. The downside is the intake bolt pattern limits choice of manifolds. If it is a low mileage motor I'd go for it.

JeepCycle

This motor is from a van. If it has higher compression but a weak cam, I can cam it and do quality valve springs before I put it in as I will be doing an Edelbrock manifold and Tubes anyway. I'm trying to check everything before I move on it.

cv67

What yr van? make sure you didnt get stuck with the crappy swirl ports

JeepCycle

I checked, it has the 062 head castings.

mcm95403

I recently rebuilt mine and used GM Fast Burn heads with a Scoggin-Dickey LT-4 replacement cam and re-used my big-port Accel long tube runner setup. With the LT-1 exhaust manifolds and the good exhaust, the car runs amazingly well. It idles like stock with just a small burble, has fantastic mid-range and pulls very well to at least 5800 rpm.

Hopefully in the next month I get it to the dyno to get real numbers.

Keep in mind that if you go with the Vortec heads, you'll need to either re-work your existing manifold or replace it with a $400+ Edelbrock Vortec TPI manifold. You can also get your Vortec head intake bolt pattern re-drilled to suit the regular bolt patter, but you'll still need to get the tops of the ports welded up to cover the taller ports in the Vortec heads.

JeepCycle

That's interesting info but it poses questions. So one can use the can use an lt4 cam in the l98? The Accell tubes are with the stock TBI manifold? Now, the fast burn heads, I am concluding that they are not LT heads. Are they an improvement over the Vortecs? I had intended to go with the Edelbrock if I use the Vortecs.
It seems that you are indeed getting the performance I am seeking, I just need to knw the details.
Thank you.

mcm95403

The cam I used is an LT-4 replica. You get the .480 lift with 1.5 rockers instead of running the 1.6 rockers used on the original LT-4, but it has the same duration and overlap. The Accel setup is a large runner base like the TPIS Big Mouth. You could also port out a stock manifold but it would be a LOT of work. If you went that route you'd also need to get better runners.

The Fast Burn heads have larger intake ports than the Vortec (intakes are 210cc). Both the intake and exhaust ports are the same as the LT-4 (except for the larger port) and are what the Vortec heads are based on. The great thing is, they have the standard bolt pattern for the intake side. The drawback is that stock center bolt valve covers WILL NOT fit them even though they are drilled for the center bolt pattern. Some aftermarket ones may fit, but I ended up using the regular old-style perimeter bolt valve covers. The other problem is the raised exhaust ports, which is why I did the factory LT-1 manifold conversion - http://marcmedina.com/LT1manifolds.html

In normal driving it drives just like stock, but when you get on it, it pulls strong. Mine is an automatic, so I also did a 2400 stall converter (stock replacement converter for a 97 Vortec V-6 S-10 truck) but if you have a stick it would be much better. I'll see if I can get a video in the next couple of days.

PM me your number if you like and I'll be happy to call you.

JohnC485

I'm in the middle of swapping a full 4-bolt crate vortec. You'll need a few parts for the 1 piece RMS, but overall I think it's worth it over the flat tappet '85, or any flat tappet for that matter.


And, calling those heads overrated for a street car...that's a bit ridiculous. They are good. =P

project C4

powerpigz-51

I would just put a decent set of aftermarket aluminum heads and intake of choice. If ya got 500 extra bucks, retro roller. Sounds so much easier, aftermarket heads will handle hi lift and 1.6's without work, etc. Cheaper, easier, more power and power potential in the end.