350 to 454 questions
 

I got a few questions it comes to swapping from a small block to a big block…
I ran into a pretty sweet deal I jumped on over the weekend. 1 year old never been ran big block 468, all new parts, forged internals, roller cam, edlebrock performance heads, Holley carb, performer intake, arp fasteners, oil pan and timing chain cover. I spent like 3500 all in. I’m new to messing with engines so I’m lost on ordering rods and rockers, looking for advice. Other questions are how straight forward is the swap? I know motors are supposed to be the same. I’m aware of exhaust being different. What can I use off the front pulley system? Different radiator? Tranny is a 700r4 I had beefed up for future endeavors like this. Rear end is Yukon 3.73 posi unit.

I’m sure I’m missing a lot of info yall might need to help a little more so just ask away. TIA

Heads Edelbrock Performer RPM454-R
Cam- comp cams 11-771-8
Carb- 750 Holley street hp 0-82751
Intake-Edelbrock performer 7562
Lifters 819-16
Pistons - SRP big block Chevy 212136

Re: 350 to 454 questions
 

You have to get big block brackets for the front pulley system. You can reuse the alt, p/s pump and the AC compressor--none of the brackets. You can reuse the distributor, motor mounts. You'll need a new transmission soon after you install the 468. You will need a 4 core radiator. It will bolt in to the same spot though. I did do this last year, don't want to do another---I'm getting too damn old

Re: 350 to 454 questions
 

Just out of curiosity, cause I hear it a lot about 700r4 trans being weak. Is it not possible to build a strong one or it just expensive to do it? I had this one built like 5 months ago and I told the guy I want to hold up to 500/500 and he said I shouldn’t have an issue with that. But I’ve always heard the 700r4 are just not stout transmissions…

Also, you have any issues with vacuum?

Re: 350 to 454 questions
 

Is this motor all togethor ready to run or just a bunch of parts?
Have you done a cam break in before?

Re: 350 to 454 questions
 

Roller cam should be ok

Re: 350 to 454 questions
 

I've had a 454/700 combo for 7 years and not sure how long it was together when I got it.
But I drive it like a 454/700

Re: 350 to 454 questions
 

Issues with vacuum? Not that I recall. The engine installed was a crate 502. I've never had a 700 last no matter who built it or however 'beefed up' it was. I went through 3 of them in my Suburban in a span of 5 years. Stock 350 tbi engine with very mild towing thrown in here and there. 700s should never have been installed in trucks. Your 700 may 'hold up' some but it won't last say more than 40-50,000 miles. So that is my experience and i've been building automatics since the early 80s

Re: 350 to 454 questions
 

I wouldn't do a 454/700 either. But ours came that way and hasn't died yet.
It will now that I've said so..

Re: 350 to 454 questions
 

But is it actually a roller cam?
Some people assume because it has roller rockers that it is a roller cam too.

And no matter what cam is used, a normal break in should be done. The cam gets lubed by oil splash. Not to mention piston skirts etc.

Re: 350 to 454 questions
 

It’s a complete long block at the moment. I have everything to put the engine together besides push rods and rockers. I’ve never done cam break in before.

Re: 350 to 454 questions
 

I ask about vacuum cause I’ve read about larger cams pulling all the vacuum and possibly losing all the vacuum for the brakes? All this is new to me so I’d almost believe everything at this point lol

Re: 350 to 454 questions
 

Do you have a pic of this motor?

What do you have for tools and equipment?
You’ll need a torque wrench and likely an engine stand.
A full inspection might be needed.

Re: 350 to 454 questions
 

I got everything I need for tools, the motors literally the only thing I haven’t done on the truck since building it. The motor sit on an engine stand right now, but I plan on buying a different one because one of the wheels is janky. I’ll post a picture of the motor when I get back to the house for the day. I had in my mind to probably take the heads off and the whole pan just so I could see what I’m working with. He did list the parts that were in the motor, but I haven’t put eyes on it yet as far as Pistons go. I don’t know how thick the head gasket are.

Re: 350 to 454 questions
 

Here is a couple photos of the engine just as I picked it up.

Re: 350 to 454 questions
 

I was hoping to see the lifters.
And a pic of the front of the motor.

Re: 350 to 454 questions
 

Here you go.

Re: 350 to 454 questions
 

Yup!
Roller rockers.
Not a tall deck.
I’d pull the heads and pan to check stuff.

Re: 350 to 454 questions
 

Pulling the pan and heads are next on my list. I was told all the internals were forged but I’ll check for peace of mind. Does it matter on the ratio for the rockers (1.7/1.8)? I’d assume I’ll need to get rockers in order to measure for the push rod length? I’m still on the fence about the vacuum issue with the larger lift cam too.

Re: 350 to 454 questions
 

Don’t worry about vacuum.
Cross that bridge when you get to it.

What’s the specs on the cam?

Re: 350 to 454 questions
 

https://www.summitracing.com/parts/c...QaAlmJEALw_wcB

I’d like a more mild/streetable cam. This one just came with the motor but I think it’s going to be a little too radical for what I’m trying to accomplish possibly? With a 110LSA, will it be super choppy (like popcorn). Not really what I am going for. It’s strictly a weekend warrior, maybe sees the road 2 times a week.